Tracy Gilman, the queen bee of Lily's group of school friends, is kind of an Australian Regina George. She's snotty, prissy, and downright mean. Seriously, she tells Lily she smells "like the water vegetables get boiled in" (27.7) and says that no one will go out with her friend Carol because one of her ears "is bigger than the other" (16.56). Not only that, but she doesn't seem to understand that she's hurt her feelings, even when Carol runs for the school crying. Dude. That's so not fetch.
Okay, so why are we talking about this creep anyway? For one thing, Lily is kind of the anti-Tracy. She may smell like vegetables, but at least she cares about other people's feelings.
At the same time, though, there's a part of Lily that longs to be like the other girls at her school: "Sitting with Tracy Gilman and the other girls at lunch and recess, Lily could take part in their conversations […] yet inside, where it mattered, Lily felt a fraud" (6.12). And part of the reason Lily allows herself to fall in with Daniel is so she can experience "something totally impractical and nonsensible" (6.20). You know—something Tracy and her posse would do.
Tracy and her friends embody Lily's desire to experience normal life as a girl her age rather than living as a sixteen-year-old with adult responsibilities. Ultimately, this life reveals itself to be not so glamorous after all, though. And luckily for Lily, she lands Daniel without having to be some plastic version of herself.