There are many places in the novel that show that Scout is young and innocent. Let me give you three quotes.
First, as we begin the novel, we see that Scout and Jem are both young and innocent. In a short passage Scout talks about her boundaries. She was allowed to go around their neighborhood and no further. This shows that they have a small world, which underlines their innocence.
When I was almost six and Jem was nearly ten, our summertime boundaries (within calling distance of Calpurnia) were Mrs. Henry Lafayette Dubose’s house two doors to the north of us, and the Radley Place three doors to the south. We were never tempted to break them.
Second, when the trial is about to start, there is talk about Tom Robinson and his accused crime of rape. Scout has little understanding of what the crime of rape is. At one point, she asks Calpurnia about rape.
“Well, if everybody in Maycomb knows what kind of folks the Ewells are they’d be glad to hire Helen... what’s rape, Cal?”
One the best passages that underlines Scout’s innocence is her interaction with Mr. Cunningham. Mr. Cunningham and a few other men come to harm Tom Robinson, and they are even willing to harm Atticus. When Scout sees this, she has no clue what is happening and she engages Mr. Cunningham in a conversation. She talk about school and other mundane things....
In fact, her innocence is what defused the potential violence.
Don’t you remember me, Mr. Cunningham? I’m Jean Louise Finch. You brought us some hickory nuts one time, remember?” I began to sense the futility one feels when unacknowledged by a chance acquaintance.
“I go to school with Walter,” I began again. “He’s your boy, ain’t he? Ain’t he, sir?”
Mr. Cunningham was moved to a faint nod. He did know me, after all.
“He’s in my grade,” I said, “and he does right well. He’s a good boy,” I added, “a real nice boy. We brought him home for dinner one time. Maybe he told you about me, I beat him up one time but he was real nice about it. Tell him hey for me, won’t you?”