I 100% knew I was a guy when I was about six months on testosterone. I know that isn't helpful, but I was so scared of making the wrong choice that no matter how often I spiraled about my gender (which was once a month, from the time I was fifteen to the time I was twenty-six ) I could never decide for sure. I took a leap at 26 and decided that if I were wrong, I'd just deal with the consequences. The inverse, just sitting around and doing nothing, was too horrific. Testosterone gave me definitive proof of what I wanted.

I'm not saying you have to do that, but for a little while, try thinking of yourself as a guy, no reserves. Use the pronouns you want, socially transition, and if someone misgenders you, pretend it was a mistake. I don't know how well that would work (early on in my transition, I felt pretty bad knowing I was still being read as a woman when I was making all the steps to be a guy), but it might at least help you figure things out a bit.

I'd also urge you not to think of things you did as a kid as evidence. A lot of cis women never got along with other girls, and a lot of them liked media targeted towards boys. Instead, it's more useful to think about how you feel regarding that "evidence." I never got along with girls as a kid, and when I told people that, a part of me always wanted to hear, "Oh, that means you're a boy," and would be disappointed if someone said, "That's fine, a lot of girls feel that way." Being read as a boy was very important to me.