I'm thankful you feel guilty over your past; what hope would you have if all those things remained buried? Tragically, that's what happens with many people.
The most important truth I can tell you is that God loves you and wants to forgive all your sins so you can be with Him forever in heaven. He loves you so much that He has done everything that is necessary to make your forgiveness possible. He did this by sending His only Son into the world to take away your sins by His death on the cross.
Let me use an example to illustrate this. Suppose you owed the bank a very large sum of money—so large that you knew you could never repay it. But then suppose that one day a very wealthy friend came along and said, "I went to the bank and paid your debt, and now you don't owe them anything." What would you do? You'd have two choices: You could disbelieve him and go on worrying about the debt—or you could accept what he did and believe it.
This is what Jesus Christ did for you! He paid the debt you owe God because of your sins—and now all you have to do is repent of your sins and believe it. Open your heart to Christ today, and thank Him for paying the debt you owed God for your sins. The Bible says, "In him we have ... the forgiveness of sins" (Ephesians 1:7). This is God's promise to you.