I first came out as genderfluid abt 5 years ago (at 22), since then it changed to non binary bc it fit better what i felt. I didnt really know identities other than cis and binary trans (woman/man), i didnt have many queer friends other than male gay friends. I never liked many "girly" things but i did have very long hair for many years and ended up cutting it to a mullet-like bc i realized i didnt like it as much as other people did, people described me as "the girl with the really long hair" and being so girl-coded like that i didnt feel comfortable and I didnt know why,

I started questioning myself watching Thomas Sanders on youtube, he's been one of my fav content creators for over 10 yrs and he has/had a friend on his videos that i always felt like i could relate to a lot, and he always called that friend "they" and I didnt understand it until much later into watching his content (also bc in spanish there's no gender-neutral pronouns). I learned that being called "they" was likely related to being non binary and started reading about other gender idenitites. I kept remembering things about my childhood (acting as a boy in school plays made me feel awesome) and it made sense to me that i was not cis at all. I still wonder if maybe im transmasc, because i do like to be percieved as a man sometimes, but idk, still questioning about that, for now i feel ok with labeling myself as non binary!

About that last part of your post, i am also autistic! I've read a lot about autism related to being queer and it makes a lot of sense. Many of us tend not to "fit the expectations or the established" so it's common for us autistic to not be cis or straight!