What is the author's style in Everything on a Waffle by Polly Horvath?

While the overall language of the book comes across as typical for someone of the narrator's age and character (i.e., an eleven-year-old girl), there is frequently the sense about the way that narrator expresses herself that her vocabulary and sentence structure are slightly more advanced than seems appropriate. Words, concepts and perspectives seem, at times, a little too mature for the character's age and education.