The first time someone saw me as a male was "by accident". It was way before I decided to sit down and think about my gender identity. I was wearing a binder (for some reason I thought binding was perfectly normal for a cis afab person?) and I think someone, in a store or something, called me "young man". From the first time I loved it. I didn't correct them, it was like a game to me. Not like a crossdresser because I wasn't even trying, I really felt like myself and I wanted to look as masculine as posible and see if I could get away with it... those little moments helped me figure out I was trans, I figured out most cis people wouldn't want to be "misgendered" and I never felt misgendered.
People would often correct themselves in front of me not sure of what words to use, and that was nice. When they asked I wanted to say I was a boy but I never did because I was afraid they would look at me for longer and notice something, but still, it feels amazing. Little kids specially, often think I'm a boy. I went to a friends house and her niece was SO CONVINCED I was a young man (at this moment I wasn't out and I couldn't tell my friend to just go with it).
I specially remember one time I was running at a park, I wasn't wearing a binder and I was wearing shorts (I have chubby legs). I sat down in a bench to do some stretches and an old man sat next to me and we started to talk. When I told him I had to keep going he said "okay, see 'ya later, boy!"... all that time talking to him he tought I was a guy? I felt amazing!!!