Many years ago, before this all became a talking point, my daughter, now in her 30s, marched into the office at the start of the school year in her primary school and told them she was a boy now, and her name was Timothy*. The school secretary didn’t bat an eyelid, passed the message to the school staff, and for the rest of the year, they treated her in every way as a boy. The following September, she went back into the office and said that she was now Maggie* again, and things went back to normal. I don’t think they or I agonised over it at all - it was just a stage she was going through.
Goodness knows what would have happened if it had been 2022 instead of the early 1990s - counselling and therapy probably. We laugh about it now. She’d just read ‘The Turbulent Term of Tyke Tiler’, which poses questions about social gender roles, and she was experimenting, which is what kids do.
Role-playing is an important part of learning. If a five-year old said that she was Princess Aurora, you’d probably go along with that until she got bored with it. Assume this is just a teenage version of the same process.
*names changed