You can’t change the past, no matter how much you may want to do so. The guilt and shame of your past mistakes may haunt you. You’ll be going along just fine and then a song or a familiar face or some other reminder will bring all those memories back to the surface. If you let it, those memories will overwhelm you and send you spiraling back down to the pits of guilt and shame from which you strove so hard to climb out.
Consider this John 21:15-19:
So when they had finished breakfast, Jesus said to Simon Peter, “Simon, son of John, do you love Me more than these?” He said to Him, “Yes, Lord; You know that I love You.” He said to him, “Tend My lambs.” He said to him again a second time, “Simon, son of John, do you love Me?” He said to Him, “Yes, Lord; You know that I love You.” He said to him, “Shepherd My sheep.” He said to him the third time, “Simon, son of John, do you love Me?” Peter was grieved because He said to him the third time, “Do you love Me?” And he said to Him, “Lord, You know all things; You know that I love You.” Jesus said to him, “Tend My sheep.
In this passage, Jesus has risen from the dead and confronts Peter about his sins. If you are familiar with the narrative of Jesus’s arrest, crucifixion, and death, you will remember that during Jesus’s questioning by the chief priest that Peter denied knowing Jesus not once but three times (Matthew 26:69-72; Mark 14:66-72; Luke 22:54-62; John 18:15-27). So why does Jesus ask Peter “Do you love Me?” three different times? Part of the reason is because Jesus wants Peter to know that He forgives him, and He wants Peter to forgive himself.
“If we confess our sins, He is faithful and righteous to forgive us our sins and to cleanse us from all unrighteousness.” (1 John 1:9)
“But God, being rich in mercy, because of His great love with which He loved us, even when we were dead in our transgressions, made us alive together with Christ (by grace you have been saved), and raised us up with Him, and seated us with Him in the heavenly places in Christ Jesus.” (Ephesians 2:4-6)
“Therefore there is now no condemnation for those who are in Christ Jesus.” (Romans 8:1)
If you have accepted Jesus as your Lord and Savior, He has forgiven you from all your sins: past, present, and future. If the God of all creation can forgive you, who are you to hold anything against yourself. Your sins are gone so let them go.