No, just 'cause you didn't feel like anything was wrong in childhood, doesn't mean you are not trans. I personally have never felt upset about my body during my childhood. When I saw my body, my mind processed it as male. I even thought my parents were lying to me about my gender, and when I found out I actually didn't have a dick, I still thought I was a cis male. That's the weirdest and most hardcore denial I have ever experienced. Even today I feel similarly, but I'm not complaining. It helps a lot with my dysphoria. Haha. Having that said, I realized I was a trans guy when I was fourteen. I've always felt this way, but it was only last year that I actually found and accepted the label. Like the others said, it really is different for everyone. It just depends on how you feel. If you feel like a woman, you're a woman. If you feel like a man, you're a man. If you don't feel like either, you are neither. And so on.