NC for privacy. Hoping someone can reassure me/help me help my baby sister!
My sister is 18. She was diagnosed with autism as a small child and is really struggling with it just recently. She self harms (doesn’t cut but she does bang her head against walls, pinches herself amongst other not very nice things)
She regularly posts vague but worrying things on social media, e.g. “I hate being autistic, why can’t I be fucking normal, I hate looking in the mirror, I am disgusting”
it breaks my fucking heart.
My DF is becoming increasingly worried for her but she won’t let him or my DSM in, I’ve tried talking to her and so has my DP but she fobs us all off with an “I don’t want to talk about it”. What can we do 

The other thing I’m worried about is that she’s 18 and has shown no real signs of puberty yet; she hasn’t started her periods, she has barely any body hair and her breasts haven’t started to grow yet. Her body shape is still very childlike. Can any late bloomers give me some reassurance here please? She will absolutely not go to the doctors because she’s terrified of needles. Sedatives don’t work on her (doctors have tried and failed to sedate her for various things as a child)
Handhold please if nothing else 