Thank you for your letter. When we're young, we often don't realize how life-changing our decisions may be for good or for evil. Only as we grow older do we begin to see it and that's especially true for someone in your position. The Bible speaks of the terrible consequences that await those who "did not choose to fear the Lord" (Proverbs 1:29).
But listen: It is not too late for you to turn to God! Yes, your life would have been much different (and much happier) if you had given your life to Christ when you had the opportunity many years ago. But why enter eternity separated from God and His blessings if you don't have to? God loves you, in spite of the way you've treated Him. If you had been the only person on earth who needed to be saved, Jesus Christ would still have gone to the cross and died for you. God loves you that much!
Right now, God is speaking to you and giving you a second chance to turn to Christ. Don't make the same mistake you did over 60 years ago. The Bible says, "Seek the Lord while he may be found; call on him while he is near" (Isaiah 55:6). By a simple prayer of faith confess your sins to God and commit your life to Jesus Christ. You cannot change the past, but you can change the future.