im pretty sure this isnt normal, im a 14 year old guy and ive been masturbating regularly for a few years now and whenever i have done it i always left the foreskin on the penis, not pulling it back. i know this is not normal as my friends told me, but now when i become erect i try to pull the foreskin back normally and i do to the point where it gets a little past the penis head, then i let go with my hands but then it just slides back all the way over my penis, the same thing happens when my penis is unerect... im guessing this isnt normal. i dont know what to do, whats gonna happen later when i sleep with someone or have sex...

my penis is 6 inches erect if it matters.