In "The Blessing Tobacco," what is the rhetorical function of the passage where David considers whom he should "smoke like" (108)?

Before lighting the first cigarette his grandmother gives him, David considers whose style of smoking he should adopt--his mother's, Paige's, or Frick's. This demonstrates that all of David's adult role models are smokers, and that he is about to cross a significant threshold into a version of adulthood dictated by his circumstances.