Hi, sorry for the click bait-y title, but there is something odd going on with one of my partners youngest. 
 He (M45) has 4 daughters, the youngest two are twins (F13). They are both involved with music/choir at school. 
We went to a small concert they had a few weeks ago, one twin was performing. The other sat in front of us with her mum/his ex, we sat directly behind. His kid was slumped all the way over in her seat, with huge headphones on. My partner gets irritated, leans forward and asks his ex to tell her to take them off and sit up, which she does. 
   Later on, partner explains to me that his daughter has been claiming she has autism, and those aren't wireless headphones, they're huge ass industrial earmuffs. 
 His ex has talked to her, and explained that no one just has autism out of the blue, so what's going on? She has never acted like sounds or anything else sensory has bothered her before. Daughter insists she is on the spectrum, claims she is "stimming" to dodge the convo.

Partner tells me he has to tell her to cut it out before they go anywhere together, and she does. He said (and I agree) that it looks like she's making fun of autistic people. But she will not talk about it with either parent.

  I do not think she is on the spectrum, although I know it takes a professional to officially diagnose. I think she may be suddenly doing this to feel special, especially as twins tend to get unfairly lumped together.

  Has anyone else here come across this? Again, she has never displayed any signs of having autism, yes I know masking is a thing and I'm not a pro, but this was sudden and performative. I'm just trying to understand!