@Snarrf It is SO common for autistic girls, particularly those who are cognitively able to become obvious and/or hit crisis point at they get to their teen years. Have a Google about autistic masking in females. This can come out an anxiety. Yes your daughter may well have read up on it online. That may have made her realise that those 'things' that she wants to do but hold on/masks are actually normal for her and she now feels freer to do them especially in front of you at home where it's 'safe'.
She might not be neurodivergent. But she might be and you owe it to her to find out. You can go about this two ways. Independent assessment (around the £1500 mark for ASD only, must be compliant with NICE guidelines including the diagnosis report to be relied upon for educational support) or via the NHS accessed through CAMHS referral. CAMHS will take YEARS, no exaggeration in my area it's around 3y at the moment.
Let me tell you about a little girl, in the 90s, who met all of her milestones, lots of them early. Who was academically advanced, bright and curious, made friends, went to parties, was a noisy chatterbox, loved loud music, behaved perfectly at primary school, and who showed no real outward signs of being autistic or concerning behaviour. The wheels started to come off a bit in secondary, she was anxious she started acting out at home and being the class clown at school. Being 'ill' all the time. Wanting to avoid going for no 'real' reason. Started to find friendships hard to navigate but not speaking up because she was ashamed that it seemed like people didn't like her. Secretly self harming but didn't know why - she has nothing to be sad about! Had awful low self esteem. Got herself suspended on a few occasions and was constantly told that she was wasting her potential and no one understood why. Labelled as a chatterbox, a disruptor, as someone who when challenged eventually by the time leaving school age rolled around didn't respect any authority. School were glad to see the back end of her.
She passed her exams, but nowhere near as well as she could have done. Went to college for A-Levels and couldn't cope at all with self organisation and independent study. Dropped out of college and got a job.It wasn't 'couldn't cope' though. She was just lazy and disorganised.
She had several jobs, never lasting long because she always ended up rubbing people up the wrong way without realising and leaving. Finally found a job that she was good at, using the skills she had but working solo mostly. She overspent wildly, compulsively and irresponsibly as a young adult, and always had issues with her weight because she couldn't control binge eating. She partied hard, drinking far too much, endangering her personal safety on many occasions and smoking incessantly. She learned to drive but it took her six attempts and until her mid 20s to pass and she couldn't understand why she was so stupid at something so simple to other people.
She eventually met her husband, settled down, paid off all debts by doing well in her job. It suited her, working quietly on her own, writing. They bought a house and had children in her thirties.
One of those children was diagnosed as autistic, very young. No one in the family believed the mum because they said they child was perfectly 'normal' - that she was just like her mum was when she was small! The mum attended courses to learn about autism to help her child because she was in shock and had never met an autistic person before, knew nothing about it.
Then came the lightbulbs moments. Two years and two assessments later, aged 37, she was diagnosed as autistic with ADHD. Life made sense - including everything that life was like as a child, teen and young adult.
That little girl is me.
Please get your daughter checked out. Don't let her get to nearly 40, with a lifetime of unexplainable behaviour behind her thinking she's a broken useless adult before she understands who she is and why she's like she is. It's life-changing to find out and at her age now it's a massive advantage.
She might not be. She might just be your perfectly neurotypical teen, being a huge pain in the arse like teens can do or neurotypical but suffering from clinical anxiety that needs to be got to the bottom of. Or she might not be, and she does need to know (as do you).
Good luck.