Your post touched me deeply, I had the same kind of experience with older boys at school. I was the same age as well.
And like you I questioned my sexuality because I fantasized about sex with other men. In the end I did act out with men.
But the main difference is I waited until I had been married for 25 years and was 46 yo before I broke my secret. That was about 4 years ago, and I have moved on considerably since then, recovery IS possible.
The guilt you feel about being "born this way" and all the other crap you feel is unfortunately 'normal' for us, but not cast in stone - we can change it.
The first and possibly most important thing we have to do is accept that we need to deal with it.
But it is my life and I have to deal with what I have been dealt.
And you've made that decision already, welcome to MS - a great place to get help and support.