Kinda the same thing here, I'm 51 and the even though I sometimes would dress in female clothing through the years, I never questioned it, I just thought it was comfortable, or what's the big deal? For years I would draw myself as a woman (I'm an artist) and again the light never went off. Then in my late 40's, I wrote a story with a Trans character in it, which is odd, since I knew virtually nothing about this. I started doing a little research to flesh in the character, opps, too much of me in everything I read. Thank goodenss for the internet, or I'd still be dumber than a box of rocks.
I've always been pretty feminine in my disposiiton, but never thought to connect the dots. I never even realized the dots lead anywhere. Still in retrospect, it makes so much sense,duhhh.
I dated a medicine woman for a while, she called me "Two Spirit." That too, was a revelation that has stayed with me.