I would say that Harper Lee has a lot in common with Scout. She has mentioned that she based the story on growing up in Monroeville, Alabama in the 1930s.
Harper Lee based her story on her own childhood, and she is describing herself when she looks back as Scout. When she describes Maycomb, she is describing her home town of Monroeville, Alabama.
Maycomb was an old town, but it was a tired old town when I first knew it. (ch 1)
Just as Scout is based on Harper, Dill is based on her friend Truman Capote (also an author). Like Scout, young Harper was a tomboy and eccentric. Like Dill, Truman was eccentric. Like Scout, Harper grew up in an era of racial turmoil, and the book was written at a time when things had reached a head.