Is it normal to question myself when i know how i feel?

This goes along with my first post. I've been over analyzing my thoughts. I asked my mom one day, how does someone know they are gay? Is it from childhood?" She says they know from when they are younger. I began to question myself because I find myself looking at other women's boobs and butt, but not to check them out to compare myself, for I am very self-conscious. I've liked boys and men since I was little and still do, however, after I asked this question I have been questioning myself and freaking out. I know that if I continue to over analyze I will somehow convince myself I am gay. If I think about it, I get extremely nervous and end up crying. It's not who I want to be. Is it a faze, or normal for a teen, like me, to have thoughts like these? I am so confused and I know I like men, however who I am does not include checking out women for enjoyment or fantasizing about them. I fantasize about men and want someone to tell that in not alone in this.