D1 I think teens now generally like a label to put on themselves, my dd has gone through various phases of believing she's something or the other. I do think she is autistic as there's been loads of traits since she was a baby and I think generally teens struggle with identity and managing difficult emotions. That's even before you throw AN into the mix.
That said I would have a line re behaviour that you will/will not tolerate. For me the line would be physical assault or threatening physical violence. At that point I'd contact the police and dd would be under no illusions that that behaviour was not okay. Shouting, slamming doors etc id chalk up to a normal teen tantrum.
I was very proud of dd Ystd, she had a medical appointment that she had to go to on her own as I was at work all day. The appointment involved her being weighed and measured and she told the nurse that she had an ED and absolutely did not want to know any measurements. The nurse apparently was very good and made it as stress free as possible.
This is from the girl who screamed and shouted at me when she was first blind weighed that I was abusing her human rights and was an evil bitch for not telling her....
It feels like a massive step in the right direction that she recognises triggers and confirms my belief that she absolutely did not want to know her weight all along.
It was also the first day in over two years that I didn't leave any food preparation for her but trusted her to get her own breakfast and lunch. She told me she got a Greggs sandwich, crisps and a spiced pumpkin latte for lunch 😊 would have loved it if she'd got herself a cake as well but still it's progress!