God forgives all our sins. There's no where in the bible says that premarital sex is a sin. But it does speak of fornication and I will let you search the passages on this topic. I believe in my own heart that the sin of fornication is from the intentions of the heart. Are you trying to become a playboy screwing all the girls you can bag? That's fornication! But if you find someone who you love genuinely and do end up having sex exclusively, I don't this is something unforgivable... after all, we are all human. Go at it with the intention of marriage in the long run and if it works out Kudos to you, if not then ask for forgiveness because you never knew the outcome to begin with. I hope this helps! If I am wrong, I am sorry for offending your views.