All of kkosach's points in the previous post are true concerning Scout's point of view in Harper Lee's novel, To Kill a Mockingbird. However, we must remember that Scout is telling her story in retrospect--many years later and from an adult's perspective.
When enough years had gone by to enable us to look back on them, we sometimes discussed the events leading to his accident. I maintain that the Ewells started it all, but Jem, who was four years my senior, said it started long before that.
... We were far too old to settle the argument with a fist-fight, so we consulted Atticus.
So, yes, Scout is recounting her tales through the eyes of a youngster (between the ages of 5-8), but it is the adult Scout reverting back to her childhood to narrate. It is not the same as, say, The Diary of Anne Frank, in which Anne narrates her entire story from a present day point of view. Harper Lee does a splendid job in making the reader forget this fact, since Scout's tale does seem so innocent and childlike. But there are many examples of vocabulary and higher understanding within the story that no child--not even the precocious Scout--could display at such a young age.
For example, Scout (the child) has to have Atticus explain "rape" to her; yet, in Chapter 1, she describes her ancestor, Simon, and his "impotent fury." She doesn't understand the term "nigger-lover," but she comprehends that the aforementioned Simon "having forgotten his teacher's dictum on the possession of human chattels, bought three slaves..." Scout speaks with knowledge of "John Wesley's strictures," but Calpurnia has to explain her church's use of "linin'. "
It is Scout's narration, but it is through the eyes of the older, wiser, adult Scout. This "adult perspective also adds a measure of hindsight to the tale, allowing for a deeper examination of events."
Scout is a child, and therefore she is naive, and she is an unbiased narrator. She does not judge, and she is not at all concerned with prejudice and racism. Since she is a child, the reader can come to his/her own conclusions about what is going on in the novel. Scout is untainted by adult experience, which allows for a pure narrative - ironically important because judgment and prejudice are huge themes in the text. We see things through the eyes of a child, and can therefore see them our own way.