Well, if it makes ya feel any better at all, that's sort of how I felt for the longest time (aside from avoiding male media - I did and still do enjoy a bit of that to an extent, although I would never ever like rap or the gangsta thing for a million years). I didn't really know that I was a girl - I thought I was one, but I knew that there was no way for me to know for sure.
The answer was clear enough when I saw that transitioning... taking hormones... and all that made me happy, as I knew it would. It was a little later in my journey that I found out for sure, after a bad sexual experiment - I had what I could call a dysphoria attack, and ended the session crying and screaming in his arms. While it was a valuable learning experience, I could probably have gone without it.
Many would suggest going to a gender therapist; I'd suggest it if you have the money for it, but to be honest, their role is relatively minor, as they can only help you make up your own mind. They don't offer much that you don't already have, that is, and getting hormones without one is possible... many places use the informed consent model. And there's always self-medding, which is, to be sure, quite risky. You'd have to be very responsible for it to not be dangerous.
It's up to you. You seem to have made your mind up already... "I discovered I was transgender," "I've been identifying as FtM," "I've always known I want to be a boy," "I'd really love to be Ian, and be called by male pronouns, and be treated as a boy," "I've tried [living as a girl] and it didn't work out"... And I'll note that the rebellion to feminine media and high-school culture is totally understandable, coming from a potential male that (strongly?) dislikes to be thought of as female.
I'm not making a diagnosis, but... probably the majority of trans individuals have a similar story.
Wishin' ya the best.