Ok, I'm putting my comments in brackets, like this ().
Jasmine was awoken in the same way as every other morning (let's just stick to this morning), a huge animal bouncing on the bed, a cold wet nose in her face and a friendly, if not over excited lick on the face. ('if not overexcited' is convoluted - I like the details, though, the immediacy of the start)
?Sheba! Get down, go away!? she protested as the huge golden retriever bounced off the bed and ran excitedly out of the room. She glanced around her bedroom with its pine furniture and baby pink furnishings(,) and realised there was nothing to distinguish this 14 year olds (punctuation wrong here, it's "14-year-old's", ditto 5-year-old) room from that of a 5 year old girl. But she liked it this way and it wasn?t as if she had that many friends over who would disapprove. (again, too wordy ... don't tell me what "it wasn't as if", tell me what the situation is) (I like the insight about her room though ... would she notice it, though? Do people really look at their surroundings with that sort of distance, first thing in the morning? Or should we maybe notice it, slowly?)
?Jas, get up sweetheart, school today?? called her mother, Joanne(,) (and do we need her name here?) from the bottom of the stairs.
Jasmine reached for her glasses from the bedside table and headed down the stairs. (lots of detail, but a bit of a leap here ... did she get out of bed? Or just fall down the stairs ) In the kitchen sat her mother, cup of tea in one hand and a slice of toast in the other, her father Lawrence who seemed ready to leave for work and her younger brother, Ben. (interesting sentence structure) At eight years old, Ben was the baby of the family. His huge dark eyes and messy blonde hair gave him an almost unique (almost unique?!? how does that work? I would just describe him, not talk about it all) appearance and that cheeky grin could melt the coldest of hearts.
?I?ve made you some breakfast, love? said Joanne, pointing to a bowl of cocoa pops, a plate of toast and a cup of tea on the table.
?Thanks, mum? said Jasmine as she sat at the table and smiled fondly (adverb! also, can you smile unfondly? seems redundant) at her dad, she?d always been a daddy?s girl (you're telling us - show us!).
?You ok, gorgeous?? he asked as he took a final gulp from his coffee and stood up.
?yeah, I?m fine?? (your formatting has come out a bit funny, which might be down to cutting and pasting? At any rate, new para when you change speakers. You're missing a lot of capital letters, too.)
?good, listen, have a good day at school(,)? he bent down to kiss Jasmine on the head and ruffled Ben?s hair(,) ?I?ll see you both tonight?. With that, he grabbed his black, woollen coat and headed off to work, kissing his wife on the way to the front door.
As the sound of the car could be heard reversing from the drive (no space here) way, Ben finished his cereal by drinking the milk at the bottom of the bowl (is he tipping up his bowl? say so) and ran upstairs shouting that he was going to get changed. He was excited by the fact that he had been bought a new Power Rangers packed lunch box which would be used for the first time today. (if it's new, 'used for the first time' is implied. Also, again, you're telling us - maybe have him shouting at his mum to make sure she's using the new lunchbox, instead?)
?I don?t know where he puts it all? said Joanne as she packed the box with everything from sandwiches to chocolate bars. (not enough detail. How many sandwiches? What kind of chocolate bars?)
?You shouldn?t give him so much? Jasmine suggested, forcing herself to eat the last slice of toast. Joanne had always had a habit of over-feeding her children (telling again! show!) but thankfully, Jasmine did not put weight on easily and Ben ran around far too much to allow the calories to settle in his body. (again, telling! show!)
?He?s a growing lad?he needs his food? Joanne protested and as an afterthought, added another chocolate bar to the box, hidden under (hiding it under? Squeezing it in under?) an oversized cheese sandwich. As Ben came bouncing back downstairs in his new, smart uniform, Joanne fussed over him and began searching for her camera. This was a yearly ritual where Joanne would take photos of Jasmine and Ben on the first day of term, to show how much they?d changed in the year since the last one (again, telling! show!). Jasmine took the opportunity to sneak back upstairs whilst (don't like 'whilst' - what's wrong with 'while'?) Joanne was distracted and closed her bedroom door behind her.
After dressing, washing and brushing her hair, (whoa, she hadn't done all this before? and if she hadn't, she didn't need to sneak off, did she, if she was going to do all this?) Jasmine looked in the mirror. She tried to see herself as the other kids saw her. Short, boring, plain with untameable brown curly hair and glasses. She was a stereotypical geek. (telling! please show! Also, this is clear enough!)
?Jas, Stacey is coming down the garden path?? Joanne called upstairs. Jasmine looked at the little clock on her bedside table. 8.25am. Was it really time to go, already?
She took one last look in the unforgiving mirror before grabbing her school bag and heading back downstairs.
?Bye mum, bye Ben?have a good day at school? she called as she reached the front door. (wait, didn't her mum take her picture?)
?Bye sweetheart? called Joanne.
?Cya!!? (gah. Surely he said 'see ya'!) called Ben excitedly.
?Hi Stace? Jasmine muttered as she closed the front door behind her.
?Hi? Stacey replied with a smile.
Stacey and Jasmine had been friends since the beginning of secondary school at the age of 11. With no friends and few social skills they had managed to find each other fairly quickly and had been firm friends ever since. They had a lot in common, both enjoyed school, both were above average in every subject and neither of them had any dress sense. They were never going to be hugely popular but they had each other and that was all they needed. (too much telling - also, you're telling us the future!)
?So, what have you been up to in the holidays?? asked Stacey as the pair walked quietly in the direction of Parkworth High School. (didn't they see each other in the holidays?)
?Not much? admitted Jasmine ?we went to Butlins for a week, that was a bit boring but I think they wanted to take Ben. Oh and the usual violin lessons, twice a week. Oh, and I started the piano?. (wait, who's her teacher, wouldn't she say?)
Stacey smiled ?I play piano? she said.
?yes I know, you played in the school concert last Christmas? Jasmine reminded her. (if they're best buddies, there's no way Stacey would be telling Jasmine she played!)
Stacey lowered her head and laughed looking slightly embarrassed(,) ?oh yeah, forgot about that? she admitted.
Jasmine laughed.
(you need commas before and after things people are saying. Lots more capital letters, too)
As they approached the school gates they noticed groups of kids hanging around in the usual spots, around the entrance of the school drive. It was kind of an unwritten rule that if you walked straight into school from this point, you were a nerd. (telling!) The cooler kids hung around for a while to socialise. Jasmine and Stacey headed straight through to the school building.
Once they reached their classroom in was like they?d never been away for seven weeks at all. The chairs, the tables, the teachers desk?exactly how it had all been left on the last day of the previous term. As they walked through the door, Jasmine?s heart skipped a beat as her eyes found Jacob, sitting chewing a pencil at his desk. Jacob wasn?t one of the popular kids, in fact, he was the opposite. (telling!) He was quiet, clever, a little odd?and he hung around with David, the most hated kid in the school, but Jasmine liked him. (telling!) In fact, she liked him more and more as each term went by and although she?d never spoken more words to him than the odd ?hello?, she was sure he liked her too. They were so suited to each other. (telling!)
?Hi Jacob? she forced herself to say as she walked past his desk. He looked up and smiled.
?Hi? he said.
David seemed oblivious to anything going on around him but Jasmine couldn?t help feeling sorry for him. He certainly wasn?t the nicest kid in the world, always fighting and swearing but he must have some decent qualities, Jacob seemed to like him after all. (telling!)
?Hi David? she said, a little quieter than usual. She wasn?t sure if she was expecting him to punch her for daring to speak to him or simply ignore her completely but to her surprise, he returned the gesture with a rather quick ?hi?. (new para for new speaker)
Unfortunately it wasn?t long before Sean came in. Jasmine hated Sean. He was quite tall and stocky with shaved blonde hair and a rounded face. He was horrible. In the first year he had stuck chewing gum in her hair and she had to have it cut out at the hairdressers. He had once blacked Stacey?s eye by throwing a blackboard rubber across the room which hit her directly in the face (yet the teacher insisted it looked like an accident so he got away with it) and he had even managed to send one teacher fleeing from the classroom in tears after she heard him calling her husband a queer. (sentence far too long) It was so unfair that decent kids had to spend their days with people like this. It was something Jasmine actually felt quite bitter about. (yes, we had worked this out! Too much telling!)
It wasn?t long before Sean began his usual ridiculing of David and knowing how quickly these things turn violent, especially with David, Jasmine left them to it and made her way to her usual desk. (wait, all this time she's been hanging out at David's desk? Doing what? You can't just leave her standing there, she's a geek, but please don't embarass her that much!)
?How come you said hello to Ginger?? Stacey asked.
?Don?t call him that? Jasmine whispered ?I don?t think he likes it?.
?Do you fancy him?? Stacey said.
?David?? Course not?why did you say that??
?Sorry? Stacey said, looking slightly taken back (taken aback isn't it?) ?I just thought?you know, with you saying hello to him?
?I said hello to Jake, I couldn?t just ignore David? Jasmine protested as she reached for her flowered pencil case from inside her bag.
(nice bit, good dialogue, good exchange)
At that moment there was a crash and David had flung himself at Sean. (tense weird - 'crash as David flung himself at Sean'? Or 'there was a crash, and when Jasmine looked up, she saw that David had flung himself at Sean'? I like the second better.) Jacob was frantically trying to calm him down whilst (while!) Sean, as usual(,) (also, telling!) tried his best to wind him up further. The entire classroom looked on in amazement, a few of the boys shouting ?Fight! Fight! Fight! Or ?kick him in, Sean!?. Thankfully (for whom?), Mrs Hillias entered the room just as it was about to kick off completely (surely it has already kicked off? I'd leave this out) and calmed them both down. (how did she calm them down?)
?Who do you think would win in a fight between Sean and David?? Stacey whispered. Jasmine wasn?t normally the kind of person to relish in violent encounters but this time, she found herself taking an interest.
?I think?.David would tear him to shreds? she whispered back.
Stacey laughed quietly and replied ?me too, shame Mrs Hillias came in?.
General notes - you have some good details. You seem a bit fuzzy on POV - sometimes we seem to see Jasmine from the outside (e.g. the Daddy's Girl thing), and sometimes from the inside. Pick one perspective and stick to it!
The dialogue is good.
And, as others have said, please show us things, stop telling us. A tiny bit of telling can be ok, but by and large, we want to see things, not be told about them. Let the reader work out that Jasmine is a geek. Let the reader work out that her and Stacey are good friends. Etc etc etc. If you go further into Jasmine's POV, you can express her opinions about things a bit more, maybe, (definately if you change to a first-person POV) but stick to things that she would actually know, and still, keep showing us things.
Looking at the other comments, I agree that the family stuff is less interesting (less vivid) than the friends/school stuff. I would leave out the start, or keep that as your background material, at least.
I don't get too much of a sense of Jasmine and Stacey as individuals, just two geeky girls. What are they geeky about? Ok, they play music, is that it?
Hope this helps. What are you planning to do with this?