They most certainly need to provide training for you about job specifics and disabilities you are dealing with. It sounds as they expect people to just know things.

Btw saying that someone might be autistic isn’t an accusation. Accusation would be saying that you stole her money. Saying that you are autistic is unwarranted diagnosis that no one asked her for. She possibly thinks you have ASD because she does. She has poor boundaries and struggles with social skills due to her own ASD diagnosis.

I don’t think your manager is overreacting, but i think she has unreasonable expectation of people naturally knowing how to do this job without much training. It sounds that she has no patience for people. I’d insist on more training.

Going by questions you asked you are assigned to work with people with ASD yet you don’t know anything about it. It’s on management, not you. I assume they knew you don’t know much about ASD, yet they hired you and don’t want to teach you. They are in the wrong