What doesn't Jem want Scout to do?

In Chapter 10, Scout laments about her father not having any unique abilities or talents. She mentions that Atticus is old and is upset that he doesn't have an interesting occupation like the rest of her classmates' parents. One day, a rabid dog named Tim Johnson staggers down the main road of Maycomb, and Sheriff Tate arrives at the scene with his rifle. Tate gives the gun to Atticus, and Atticus shoots Tim Johnson above his left eye, killing him instantly. Jem and Scout are both in awe of their father's marksmanship abilities and wonder why Atticus never told them that he had the best shot in the county. Miss Maudie tells the children "People in their right minds never take pride in their talents" (Lee 62). Scout then tells Jem that she cannot wait to go to school and tell her friends about Atticus' marksmanship abilities. Jem says, "Don’t say anything about it, Scout...I reckon if he’d wanted us to know it, he’da told us. If he was proud of it, he’da told us" (Lee 63). Jem wants to be a humble gentleman like his father which is why he doesn't want his sister to brag about Atticus being an expert marksman.