What are some quotes and explanations that show ageism in the novel To Kill a Mockingbird?

There are several examples of ageism throughout the novel To Kill a Mockingbird. According to the Merriam-Webster dictionary, ageism is discrimination against a particular age-group, especially the elderly. At the beginning of Chapter 10, Scout mentions,

"Atticus was feeble: he was nearly fifty. When Jem and I asked him why he was so old, he said he got started late, which we felt reflected upon his abilities and manliness. He was much older than the parents of our school contemporaries..." (Lee 118).

Scout and Jem are ashamed of their father's age. Scout also mentions how her father refuses to play tackle football with Jem because he is too old. Their prejudiced feelings towards Atticus would classify as ageism. They feel that Atticus is inadequate when compared to their friend's younger parents.

There are also several scenes throughout the novel that depict Jem displaying prejudiced feelings toward his sister because she is younger than him. In Chapter 14, Jem tells Scout not to antagonize Aunt Alexandra because Atticus has more important things to worry about other than disciplining her. Scout responds to Jem by saying that Atticus doesn't worry about anything. Jem then says,

"It's different with grown folks, we---" (Lee 184).

Scout doesn't wait for Jem to finish his sentence before she begins yelling at him and eventually takes a swing. Jem felt superior to his sister because he was four years older than her, thus making him more intelligent than Scout in his mind.