August asks Mom to buy him a new plain duffel bag to replace his Star Wars one for the nature retreat. He doesn't want to be known for liking Star Wars and knows that he needs to be careful with his reputation. He mentions that the two Maxes will never live down their love of Dungeons and Dragons. August explains that he's trying to ease out of the "Star Wars thing" in general because unlike his face, it's one part of his identity he can do something about.
The fact that August never says anything about whether the Maxes are nice, mean, smart, or funny shows that as much as August tries to reject the social structure, he buys into it when it says that kids will be known for one thing only. August also contradicts himself when he insists he can control how he's associated with Star Wars, as the Maxes clearly can't control their association with Dungeons and Dragons.