I think you have made a good choice for your theme, and one in which there are plenty of examples to be found in To Kill a Mockingbird. If you have read the first few chapters, you are probably already aware that Scout seems to learn a great deal more about life outside the classroom than within. She does not care for her first grade teacher, Miss Caroline, who is a new teacher fresh from college with modern ideas but little life or classroom experience herself. She insists that Atticus stop "interfering" with her own educational processes and leave the teaching to her. (Atticus' and Scout's reading time each evening is one of her favorite bonding times.) Later, Scout learns that Miss Gates (another teacher) does not always practice what she preaches.
Scout's time with Jem and Dill, Calpurnia, Miss Maudie, and even with Dolphus Raymond seem to provide her with greater experiences than she finds in the classroom. Also remember that Atticus and his brother Jack did not go to school; they were self-educated at home. When Scout wants to quit school and be taught at home herself, Atticus reminds her that times--and laws--have changed, and that it would be illegal for her not to attend school.
I could only look around me: Atticus and my uncle, who went to school at home, knew everything... I knew nothing except what I gathered from Time magazine and reading everything I could lay my hands on at home, but as I inched sluggishly along the treadmill of the Maycomb County school system, I could not help receiving the impression that I was being cheated out of something. (Chapter 4)