Moses killed an Egyptian, ignored his people for forty years, ran away for another forty years, and delivered a people from an oppressive situation and gave them a means to honor God.

Acts 7:35 This Moses whom they rejected, saying, Who made you a ruler and a judge? is the one God sent to be a ruler and a deliverer by the hand of the Angel who appeared to him in the bush. 36 He brought them out, after he had shown wonders and signs in the land of Egypt, and in the Red Sea, and in the wilderness forty years.

Neither time, nor people, nor past sins can block the calling of God. If we would choose to see ourselves the way God does, rebuking our opinions, doubts, fears, and impatience for submission to God, then the greatness God has called us to can manifest and impact positive change for ourselves and others.