In the novel To Kill a Mockingbird by Harper Lee, what are some quotes in Chapter 14 that impact the theme of education, bravery or loss of innocence?

When you say "impact," I assume you mean "relate to" or "represent." 

For bravery, there are two instances that stand out. First Jem believes there is a snake under the bed and gets a broom to remove it. Scout even asks if he thinks it really is one. This is brave of Jem, to do. Second, he finds that it is not a snake, but it is Dill hiding under the bed because he has...

When you say "impact," I assume you mean "relate to" or "represent." 

For bravery, there are two instances that stand out. First Jem believes there is a snake under the bed and gets a broom to remove it. Scout even asks if he thinks it really is one. This is brave of Jem, to do. Second, he finds that it is not a snake, but it is Dill hiding under the bed because he has run away from home. He stole thirteen dollars from his mother and made his way to Maycomb. This is also brave. Dill is very young and very little to be running away and especially so far by train all by himself.

For loss of innocence, I think immediately of the first part of the chapter where Scout asks Atticus what "rape" is and he answers her honestly. Although she still does not fully grasp what it is, this is the beginning of her maturation and learning very adult terms for very adult actions. Atticus does not keep this information from her and answers any questions she asks with honesty and care. This same instance could also fall under the theme of education. While it is not traditional (in school) education, this conversation is more about educating Scout about the world she lives in and is responding to.