My inherent grasp of body language is just different; I instinctively think someone's using body language the same way I do, and use a consistent, readable, mildly nonstandard way of showing emotion unconsciously. When I'm with others who use the same style, I have abilities to rival an average NT's ability with other NTs. So I could make use of it; I do have the wiring to hear words and parse body language simultaneously.
On the other hand, NT body language is generally awful for me to process at all (I bet you could tell an NT that when you slapped them and spat at them it meant true love, but they wouldn't feel loved when you did it; it's like that). I'm nervous. I don't have the early training that they do. My whole life has been spent learning that going into a social situation means laying my life on the line. I don't think, at this point, being highly skilled at interacting with NTs is in the cards for me. But I think I have the inherent wiring necessary to be successful at it, if only circumstances were different. If maybe someone had started not by saying I suck at this, but that my body language exists and is valid, and they were teaching me how a lot of other people do it, instead of how it's properly done.
Too late for me. Not too late for the next generation of people like me.
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I'm using a non-verbal right now. I wish you could see it. --dyingofpoetry
NOT A DOCTOR