I remember the character showing immaturity when Scout believed the rumors about Boo Radley. These rumors created fear in everyone in town. These rumors lead to her and Jem trying to peek inside the Radleys house after Atticus had told them to stop disturbing them because they were just normal people.
I remember the character learned from/by experiencing the trial along with atticus. Scout learned how unfair the people in her town could be. Both Tom and Boo were judged unfairly.
The character showed growth by: When both Jem and Scout was saved by boo, she decided that the best reward that could be given to him is to not make a hero out of him, instead he should keep his privacy. This shows that she has learned from the mockingbird lesson Atticus had told her about. She would not kill Boos mocking bird by making a hero out of him.