Ponyboy is really the central character in this novel and intended to be the primary lens through which the reader "sees" the story. He matures on many levels during the course of the novel even though not much actual time passes. He is petulant and jealous that Cherry does not think of him romantically and is instead interested in Dally Winston. But eventually he understands that the two of them have things in common and can be friends to one another. Ponyboy also is able to understand that Johnny's death is a major event and epiphany in his own life. Even though Johnny commits murder in self-defense, he shows his courage and compassion in helping rescue the children from the burning school. His injuries cause his death and his dying words to Ponyboy, "Stay gold" show his depth of feeling and wisdom. Ponyboy takes this message to heart and decides to tell the story of his youth (ostensibly the conceit of the novel's setting).
He got tougher and is not afraid of hurting anyone anymore.