Wow, 2 very similar stories to mine... I didn't know how I felt until I was about 11. At least, I didn't consciously realize the reason I felt the way I did. From some of my earliest memories I have always hated the thing between my legs. I tried to hide it because I was embarrassed to have it. Still am, to be quite honest. In elementary school I never wanted to play with the competitive boys, but didn't mind playing fun things with the others. I couldn't understand the obsession with football and baseball at all, so I got into soccer so I wouldn't have to use my arms. I also prided myself on trying to be as flexible as the girls at recess and played hopscotch and jump rope. On a conscious level I knew I was a boy, but on a subconscious level something wasn't clicking.
My first realization came at a friend's house watching Ranma 1/2. Before this, I had always assumed boys just pretended to like being boys. But Ranma wanted to change back to a boy every time he was turned into a girl. So I started actually paying attention to those around me and it became obvious that other boys did indeed like being boys. Why it took me until I was 11 to realize this, I have no idea. But at this point I didn't know it was possible to do anything about it. My parents were pretty much nazis regarding anything to do with sex, and I didn't even know girls had different parts until I was maybe 8. (On a related note, I didn't know what masturbation was until I was 19. Yeah, I was sheltered) I eventually was able to use the internet to figure out what I thought I was - a crossdresser. But none of them wanted to be a girl, so I kept searching and years later found the website of a girl around 18 years old that was on hormones. I finally found the word for what I was. I didn't read about Richards and Jorgensen until I was in college, where I was finally free to do research away from my parents' prying eyes.
The internet didn't convert me, it just helped me find what I'd be looking for my whole life. Without it, who knows where I'd be right now? Probably dead.