I really can't understand guys who don't realize they're gay until after their 20s

I'm looking for honest answers here. The reason I have trouble understanding that is because ever since I was a kid, I knew I liked guys. There was NEVER any doubt in my mind, so I didn't have the whole "I'm confused" "what's wrong with me" phase.I was closeted until I was 20 (I'm 25 now), but I never even tried to have a girlfriend because I knew it wasn't going to work.