i think you just need to relax. i think it's pretty natural for someone your age to get turned on by pretty much anything (or nothing). i think you're too young to be looking at porn. i know you're probably rolling your eyes at me for saying that, but you are not mature enough to understand what your body is telling you in those situations, so porn does you zero good.
allow yourself to grow up a little. don't worry about sexual indentity issues. just be yourself. you're completely normal. i'm a female, but when i was your age, and i realized i was "popping out here and there" i had all kinds of feelings i didn't understand. just give yourself some time.
by the way, i'm 26 and i can tell you that a lot of what you see on porn is NOT NATURAL, and it's not a good guide to understand what adults do when they make love. you're putting too much pressure on yourself...and it's not necessary.
good luck,
jasmine