Girl gets a makeover at a beach and one of her friends drowns

i remember reading this when i was very young its set in a beachy place, this girl whos name escapes me had chestnut brown hair and the onyl thing i knew she did is that she cut it into a bob. then later into the book her and alot of friends are at a party and while shes with a boy another boy drowns in the ocean abd shes devastated.