Being Nikki. Meg Cabot (Airhead Trilogy)

Supernerd Emerson Watts is getting to grips with life in the body of Supermodel Nikki Howard, and finding that the celebrity lifestyle is a lot harder than it looks. The bikinis are teensy, the heels are sky-high, and no one seems to care that Nikki's life is on the verge of falling apart. With too many hot men chasing her, and too many big problems to hide, it's up to Em to keep things together - even if her heart is breaking.