Historical Fiction; Young Adult Lit
Since the book is set during history (that is, real events), but it's about fictitious characters, we call it historical fiction. Sure, this could have happened during the Vietnam War, but there's no proof that it actually did to a girl named Jamie. The cool thing about this approach is that we're not learning about one specific family and their real-life experiences; instead, Jamie and her brood could represent almost any family living through the war. It makes the story much more universal. This accessibility combined with the simple language of a twelve-year-old narrator and main character also puts the book firmly in the YA lit genre.