It says in the Bible that God forgives us if we believe in Him, and ask for forgiveness. That does not mean that God has forgotten our sin, but He chooses not to bring up our sin again.
Another thing to consider is what Peter said in (Acts 10: 34) “Of a truth I perceive that God is no respecter of persons”) God said here He doesn’t apply any particularity when He forgives. God does not choose one person over another. He forgives all who believe in Jesus Christ.
This then brings up another important point you should consider. If you use the same standards of not being particular as God does, you should forgive your self. If God has already forgiven you, shouldn’t you? It is as important to God that we forgive others of their sins against us. I have a hard time with this one myself some times.
Forgiving yourself is really not about forgetting the sin, but putting it out of your mind and not dwelling on it anymore. It is not good dwelling in the past; the Lord wants us to move forward in our lives. The longer you dwell on that past sin the deeper the negative feeling about it grows.
You’ll get moody and short tempered with others around you, when you get this way. This is a good way to hurt others you love.
So leave the burden of your sins to Jesus Christ who already paid for them. Ask Him for forgiveness and live your life in peace and happiness, and thank Jesus Christ for the sacrifices He made on our behalf.