Hi OP.
The bookings with the trainer and classes sound fab. They will really help.
It's hard to say about the jumper incident but I suspect something called extinction bursts. These are when a previously rewarded behaviour suddenly does not earn the same reward. Before the dog 'gives up' they often escalate the behaviour to see if they can get the reward that way.
I think of it like pressing a key on a keyboard. I press the key and the letter A appears. That is my reward. However, if I press it one day and the A does not appear then what's the next thing I do? I hit the key harder. I escalate my behaviour to see if that works. Eventually I'll give up if I never get my A.
Your dog wanted to play. She realy wanted to play and my guess is that jumping up has resulted in something that looks like play or fun to her. Maybe not in your home but someone has shrieked, yelled, run, waved their arms or whatever. That is very exciting and is a bit like play. Wen her normal trick of jumping up didn;t work, she tried something extra.
So, she jumped at you in excitement. You stopped play. She thought, let me try something more to see if I can coax this human into playing again. So she grabbed at you, much like she might grab at another dog to goad them. Growling is also an expression of play sometimes.
IF the extra effort results in what she wants, she's more likely to do the extra thing again. If it doesn't, the chances are she'll drop it quite quickly. She's experimenting. Seeing what works.
The reason why a one to one trainer is a good plan is that they can observe (hopefully) and make an informed guess as to whether the above is what is happening - the dog is just getting over excited about play and frustrated when it stops - or if it's something else.
This tendancy to over excite is why children and young dogs need supervision. Children can easily over excite a dog without even trying and rarely know what to do when that happens, plus they get scared and scared children can be just as exciting as playful ones. Sadly.
Each dog is slightly different but a good trainer will help develop tactics to diffuse stuations like the jumper one that work for your dog. ne way might be to work on a alternative behaviour and make sure she knows how rewarding that is.
Examples:
- I had an emergency stop with my dog because I like rough housing with him but wanted to ensure I could stop him mid way if I needed to. Outside of the lay setting we practised me putting both my hands up and saying "Stop!" and him freezing however he was positioned. We practised and practised until he was really good. The I started to use it in play when it didn't really matter. I said stop, he stopped and a few seconds later we continued.
- A really strong "go to bed" behaviour can also work. Practise going to a bed or mat and make sure that every single time this happens the dog gets a realy brilliant reward. Roast chicken, cheese, a throw of the ball, a new toy. Repeat until the dog only has to hear "go to bed" and she runs to the bed to see what will happen. You are then ready to slot it into play time. Still reward her, even if you sent her to bed to stop her doing soemthing naughty. She cannot run to her bed AND jump up at the same time - it's impossible - so it's a great way to divert her.
The PP was correct. Bringing up a dog is a leap of faith. You need to know you're training will work in the end, which is again why getting a trainer to support you can help.