I'm a 17 year old Christian, and I'm not a virgin. Does that mean I'm going to hell? I don't think so. I just don't understand what makes sex so inherently evil. I know what the bible says, but WHY?
Repenting of your sins will apply the atonement's healing power of forgiveness and the Lord will remember your sins no more. He died for us as ransom for our sins. The unrepentant sinner will not be forgiven. "The Lord cannot look upon sin with the least degree of allowance."
This is a very in depth answer, but I'll try to keep it short.
First, sex is not inherently evil. Sex is wonderful and spiritual, when expressed and experienced appropriately.
God ordained man with the power of procreation. Procreation is bringing God's children to the earth. That is a serious responsibility, and God would have us bring children into the world in an ideal situation with two committed, loving parents to raise children with the guidance of the doctrines and commandments of the Lord that they may be raised up at the last day, counted worthy and inherit the blessings of the kingdom of God.
The misuse and mockery of the power of procreation is what offends God and jeopardizes a child's right to be raised in an ideal situation. Our mortal bodies are a privilege, and our bodies are temples of our spirit, and the spirit of the Lord is also in us and when we misuse our bodies, the spirit of the Lord is offended and withdraws from us.
Fornication results in bastard children, who have been forfeited the right to experience mortality as God intended and that is the blame of the parent.
Our mortal existence is short, but extremely important. There are things we experience, learn and go through that we can't in heaven. Jeopardizing another's only opportunity is a big deal.
Not only that, but self-control is also something that God expects us to have. Learning to be masters of ourselves physically and spiritually, not falling to the weaknesses of the flesh.