A great question with no answer! Non-Binary is still my go to answer since, well, it's an umbrella term for anything that does not fit within the constraints of binary gender, but it's hard for me to even say I relate to gender even as a concept? Humans are weird, dude.
As for what led me to figuring that one out, idduno! I was never told growing up "you must present in x way and be a man", so I sort of never really had any desires to present as my assigned gender. I sort of just... didn't care for gender stereotypes and I never felt like I could relate to just "men" or just "women". I eventually decided that gender is something that I just don't want to identify with? I could probably write a blog post about this explaining it better.