Look up Alan Pease for body language.

It is a difficult path to walk. I learned most of it intuitively as a young child. When I saw a gesture, it would trigger panic, almost certainly creating a self fulfilling prophecy. I also faked my body language to hide it from others, making me near impossible to read. As a young person (under 10), it was a social disaster.

Just so you know, everyone is on the spectrum. There is a threshold that makes it clear if you are autistic or not and often relates to under/over sensitivity of senses. My son is sensitive to sound and light (as an example). He also struggles to string tasks together and can't organise anything. They're all common traits.