Mates before dates- Brad Simpson fanfic

Zara and Anna had always been best friends. Since as long as they could remember. Everything's fine until secondary school starts. Anna changes and Zara still stays her best friend even though she knows that Anna is not the same person she used to be. Now they're in year 11and Anna's got a new boyfriend. Bradley. Zara hates Brad and doesn't know how any of this is going to work until that one person...