No, it's never too late to turn to God. We may get fed up with people who keep hurting us and decide we won't have anything more to do with them, but God never does. The Bible says, "The Lord is compassionate and gracious, slow to anger, abounding in love" (Psalm 103:8).
In fact, God is willing to forgive anyone, including you, who truly repents of their sin and turns in faith and trust to Jesus Christ for the forgiveness they need. God loves us, and Jesus Christ came into the world to bridge the gap between us and God -- a gap caused by our sin. He did for us what we could never do for ourselves, by taking upon Himself the penalty for our sins. God's promise is for you: "If we confess our sins, he is faithful and just and will forgive us our sins and purify us from all unrighteousness" (1 John 1:9).
Yes, you've wasted much of your life -- and those years can never be recovered. (Perhaps God will use your letter to warn someone about the folly of leaving God out of his or her life.) But isn't it better to face the future with God than without Him? And isn't it better to face eternity with Him than without Him?
By a simple prayer of faith tell God you know you are a sinner, and you want Jesus Christ to come into your life today. You'll never regret it.