All We Know of Heaaven: a novel by Jacquelyn Mitchard

Sixteen-year-old best friends Maureen and Bridget are in a terrible accident where Bridget dies and is incorrectly identified as Maureen; but when Maureen recovers, she must deal with the repercussions of the accident as well as the loss of her best friend.

True to life story of mistaken identity that leads to heartbreak and ultimately conflict between two families that are never quite the same.