I'm very thankful you have given your life to Christ, even at this late date. Yes, your life would have been different if you had come to Him earlier. But God can certainly use you to challenge people your own age to face their need of Christ, and remind them that it's not too late to give their lives to Him.
Frankly, it's somewhat unusual for people your age to turn to Christ. That isn't logical, of course; after all, death is growing closer for them, and they ought to be thinking about eternity. But sin hardens our hearts, and after a lifetime of ignoring God, a person finds it very hard to hear His voice. The Bible warns, "A man who remains stiff-necked after many rebukes will suddenly be destroyed–without remedy" (Proverbs 29:1).
Pray for your friends who don't know Christ, no matter their age, and ask God to open their eyes to their need of Him. Then ask Him to help you love them for Christ's sake, and to share His love with them. It isn't too late for them; the Bible says, "Now is the time of God's favor, now is the day of salvation" (2 Corinthians 6:2).
The Apostle Paul was very opposed to Christ as a young man, and only later came to faith. But look at all he did for Christ! Make your remaining years count for Christ no matter what the past has been.