Rory Swenson just cannot wait to be 12, that magical age at which her parents will lighten up and allow her some independence. She’s been promised that she can get her own cell phone, get contact lenses and attend a boy-girl party, among other things. Just as the long-awaited birthday arrives, Rory and her friend are selected to be extras in a movie being filmed at their school. As Rory begins to tick off items from her list, catastrophes begin. She learns that she is highly allergic to both gold and plant-based make-up, and she mangles her legs when she tries shaving. None of this makes her look good on camera. Rory’s amusing disasters foreshadow the lessons she learns at her first boy-girl party, from which she escapes rather than participate in a kissing game: Growing up doesn’t have to happen all at once, and it isn’t always all it’s cracked up to be. A couple of clunky plot points notwithstanding, Mass provides a pretty entertaining and solidly worthwhile read. (Fiction. 8-12)