Did you ever hear of Moses? Before God sent him to free the Israelis he spent 40 years hiding out in the desert because he killed an Egyptian. How about Sampson, He hung out with the enemy and had a prostitute for a girlfriend. Most of you have probably heard of David. He committed adultery AND murder, but he repented and though he was punished, God forgave him and called him a man after His own heart. And then there is Paul, he went around looking for Christians to kill, until he became one. In the book of Ezekiel chapter 18 verses 21-23 God said " But if the wicked will turn from his sins that he hath commited, and keep all my statutes, and do that which is lawfull and right, he shall surely live, he shall not die. ALL HIS TRANSGRESSIONS THAT HE HATH COMMITED, THEY SHALL NOT BE MENTIONED UNTO HIM: in his righteousness that he hath done he shall live. HAVE I ANY PLEASURE AT ALL THAT THE WICKED SHOULD DIE? SAITH THE LORD GOD: and not that he should return from his ways and live.  
Your not too bad for God if you really want to change, but it is YOUR choice not HIS!