My apologies as this might all come out a bit garbled but I'm at a loss as to how to handle this situation. I hope I've put this in the right place but I'm sure it'll be moved if not!
DD12 goes to a stonewall school (very limited options, good acedemic scores, would've avoided it if I could) and within months of starting had declared herself trans. Never been on the radar before, had mixed interest covering both typically gendered ideas.
In the past year we've pretty much ignored/gone with it. Hair has been cut, no problems with that, clothes have changed as and when needed and it's been very much a that's lovely dear attitude from us. But she's become increasingly agitated that we won't use her preferred pronouns and continue to use her dead name.
She has one particular friend who is also travelling this path and her behaviour and attitude is always worse after spending time with them. We're now onto why we won't let her have a binder 
School have spoken to me to request a name change on documentations which I didn't allow but explained I was aware friends would call her her 'new' name but that I treated it very much like a nickname. I have since discovered it has been changed on the register, however all correspondence I receive has her given name.
But I'm lost has to how to move forward, fight against it and it will become even more appealing but ignoring it doesn't seem to be working either.
If I thought these were her own feelings or if it continues as she gets older and is able to actually discuss it without tantrums and door slamming I will obviously support her but for now it seems entirely like brainwashing and I don't really know how to move forward with it.