Love Is for Losers by Wibke Brueggemann

Fifteen-year-old Phoebe thinks falling in love is vile and degrading, and vows never to do it. Then, due to circumstances not entirely in her control, she finds herself volunteering at a local thrift shop. There she meets Emma, who might unwittingly upend Phoebe's whole theory on life.
Binding: Paperback / softback