I'm quite late posting this, but as Skeezyks said, how a person feels about their gender isn't always binary - that is to say, either all male or all female. Some people may entirely identify as non-binary. It's also not that uncommon for someone to be inderferent about their gender. Some may only change their name and have top surgery for a flat chest or maybe just a smaller chest, some might only want a change in pronouns, etc. Really, it's all about what feels most comfortable to that individual. It is interesting that it seems many people who are on the autistic spectrum don't fit into the neat little box of "female". So you're certainly not alone in your experience!

I can definitely understand not wanting those physical characteristics. They can be pretty annoying at best for anyone who deals with them so it makes sense that it might be even less tollerable for some with autism like yourself. That part itself might not have to do with gender specifically as it sounds like it may be more about how something physically feels to you than it's association of being "male" or "female. So the physical aspect might be a different thing than how you experience your gender - if that makes sense.

Do you have a therapist you could talk about this to?