No, it isn't too late -- because it is never too late with God. God loves you just as much now as He did when you were a teenager and yearns for you to turn to Him so He can welcome you into His family forever.
The Bible does, however, warn us about the danger of thinking we can wait until the last minute to turn to God. For one thing, life is uncertain, and we never know when it will come to an end. Jesus told about a rich man who ignored God, deciding he'd spend the rest of his life in comfort and ease. But God called him a fool, because "this very night your life will be demanded from you" (Luke 12:20). Don't let this happen to you.
The Bible also says that we can turn away from God so much that our souls become calloused and hardened, and we're no longer able to hear Him speaking to us. The Bible warns, "A man who remains stiff-necked after many rebukes will suddenly be destroyed -- without remedy" (Proverbs 29:1).
God is speaking to you right now; don't turn away. Instead, turn to Jesus Christ in repentance and faith, and ask Him to forgive you and come into your life today -- and He will. Then learn to walk with Him every day, as you pray and read His Word and have fellowship with other believers.