I started playing as a guy on Neopets when I was 9 or 10, probably. Made an account with my gender set to male, came up with a male identity, went to insane lengths to prove that I was male. At one point I took a picture of my arm hair and said "does that look like a woman's arm?" It didn't, but the fact that I was so damn obsessive about proving to them that I was male...? Very odd indeed. I actually sort of changed identities very often; identified with characters, with people, always men... Different names, different stories, always the same personality. But I was having trouble coming to grips with who I was.
That was the first time I ever felt good about myself. I remember feeling, over time, that I was becoming more like my online self as I started to wear masculine clothes and present as more male... I remember feeling a great relief and comfort about that. My "online self" was a representation of my "real self", one I apparently knew subconsciously from a young age.
The fact that I was always putting off meeting or talking to my online friends (and still do, with some of them) until I "transitioned", which was a very vague but expected part of my life, just kicked me into action. It was always there; the knowledge that one day, I'd get a sex change, before I even knew the logistics of it. I didn't ever see it in popular culture, I just knew that there had to be some way to make my body male and I knew I'd have it done some day, and I started putting everything off until it one day happened. Having those friends and those experiences made me realize that I needed to start living, really living, as me.