Twyla narrates the story from a first-person perspective. Her tone is humorous and at times defensive, as if she is trying to justify her actions to the reader and create rapport with them. She clearly feels guilty and vulnerable in some way and uses her tone as a deflection technique. With each narrative interjection, the reader senses that Twyla is trying to convince her audience and herself of her good intentions.
There is also an air of uncertainty in the writing; Twyla frequently doubles back to correct her account of an event, or casts doubt on its real or perceived significance. Her situational perspective is never lost from the narrative—it is always clear that she is giving her personal account of an event, and not an objective or definitive one, as if she is scared of being "disproven" in some way and trying to hedge against misunderstanding. This further contributes to the feeling of defensiveness that weaves through the story.
Twyla is not an unreliable narrator in the classic sense, but her tone indicates a person who is struggling to make sense of their confusing experiences. She has two competing desires: to be affirmed as a "good" person, and to not accidentally tell a lie. She wants to prove herself, but her understanding of her memories prevents her from putting forth any kind of objective evidence. This is why she often seems to be in conflict with herself as she narrates.