I think I might have answered this, but for me, it started as a teenager. My 1st cognitive moment happened in a bar. I was under age, as was several others in there that night. There was this girl, probably a college girl, and I noticed her sitting at the bar, so half drunk me decided to go buy a drink and start a convo. As I was doing so, I got a sudden feeling of wanting to wear what she was wearing, look like how she looked. I wanted to BE her. Freaked out would be way to mild of a statement for how I was feeling about this. I blamed it on the beer and went straight home. It didn't take long at all for those feelings to start re surfacing. Imagining myself being one of the cheerleaders, I started noticing all the girls outfits.... There the intense denial and repression was started. A battle that waged on for 30 years, one day finally I waved the white flag.
Now, looking back, I was not one of the bigger tougher boys. I was kind of fem but didn't realize it at the time. I had a much better relationship with my father than I did with my mother. I am an only child, and my mother being quite a bit anti social, there were never many people around when I grew up. I was sheltered quite a bit. Had things been different, I imagine I likely would have discovered it sooner.