Although the events happened in the past, the narrator is now much older. How is the adult different from the child?

As adults we bring a different understanding to the events of our past. For example, Scout learns to admire her father without some of the cynicism or prejudice of the townspeople who are against his actions as a lawyer for a black man. Scout can also look at her personal behavior through the lens of what she has learned as an adult. She understands the people around her whose actions do not make sense during the time she was a child. She knows more about the world and will apply the knowledge of her childhood to all other parts of her life. The adult is the one who does not act impulsively.