Yes, this thread is really affirming.

I was one of those really young ones. I like how others have talked about roles. Long before I understood gender I identified with men. My dad, brother, neighborhood boys. I played with boys. I played boy games. When I was about 4 I was with a bunch of boys and they had a contest to see who could pee the farthest. My brother (older) told me I couldn't do it. I was devastated. I was supposed to be a boy.
My family was insane and abusive but I still fought all things girl. By the time I was 6 or so, they'd pretty much given up trying to put me in dresses or girl clothes. At that time we were pretty broke so I was wearing my brother's hand me downs and I loved it. I once got a doll as christmas/hanukkah birthday and sobbed.
When I started school there was a boys and girls line. I got in the boys. I found it upset and confusing that I kept getting laughed at and told to go into the girls. I tried to pretend I was just joking while still getting into the line I felt I belonged. When I got enough trouble from the teacher that I gave up on the boys line I would try to stand somewhat out of the girls line since I didn't belong there.
When I was 11 there was a show on transgender on the Phil Donahue (anyone remember that show?). I turned to my mom and said maybe I could do that. My mom pointed out the people on the show were all men turning into females and she had that tone that said "drop this conversation now".
Then puberty hit and I went through a stage where I tried really hard to be a girl. I tried makeup, got a perm, etc. I hated it. I hated my body changing, but it also seemed inevitable so I gave up. By that time my family situation had gotten so bad I was in survival mode anyway.
Someone else mentioned this. I have always *hated* having my picture taken and I never quite understood why, until recently. I hated seeing that female in the picture. It was not me. Now when my picture gets taken I don't experience that dysporphia. I tended to avoid looking in mirrors and when alone would often stick my tongue out at myself. It was partly because I didn't like what I saw and partly because there was this disconnect between the image and myself. Seeing the goofy, tongue sticking-out me in the mirror would confirm it was me.
I also developed an eating disorder. Some of that related to past abuse but a lot of it was trying to get rid of any female feature. If I could just get flat enough... of course that was an unachievable goal. The only time I truly liked my body was when I was doing physical activity.
Ok, that's a super long answer. I've never been able to answer that question before so sorry I said so much. And thank you for this post.