Why does Willow hate her job at the library in the novel, Willow?

Willow works at the University Library to make extra money to help David and Cathy make ends meet since moving in with them. Even though she is only in high school, she is given a job at the library because of David's pull and influence at the university. Willow hates her job because it reminds her too much of the library at her parents' house and her father's love of books before he died.