From what you say, you've made many mistakes in life, but the greatest mistake you could ever make would be to assume there is no heaven or hell, and that this life is all there is. Jesus warned, "It is better for you to enter life maimed than ... to go into hell" (Mark 9:43).
But I have good news for you: You don't have to go there! God loves you, and He doesn't want you to enter eternity without hope and separated from heaven's joys forever. And He has made this possible by providing a way for your sins to be forgiven and cleansed -- completely and totally. That way is Jesus Christ, who came from heaven to take the judgment that you and I deserve, by dying on the cross for us. We deserve the death and hell that He endured -- but He took our place.
Don't gamble with your soul, and don't assume you can never be saved, for it's not true. Instead, repent of your sins and put your faith and trust in Christ for your salvation. God's promise is true: "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). Commit your life to Jesus Christ today.
Then pray for your friends who think they don't need Christ but can make it to heaven on their own. May they face honestly their need for God's forgiveness, and by faith ask Christ to come into their lives.