Four stars, because Thea's narration is so raw and honest, just like how a sixteen-year-old girl's should be.
Can't say I like her character though, as I find her annoying more than half of the time. But I think that's what makes this novel work--I'm torn between hating her (and her little group, and their desperate attempt to be different from everyone else) and liking her for being true to herself, no matter how annoying it could be at times.
I think a lot of teenage girls will be able to relate to Thea as a person. A lot of adult readers will be irritated at her shallowness, until they remember that they've gone through adolescence once upon a time, and chances are, they've been annoying to older people too.
(Isn't it annoying how much I used the word "annoying" in this review? Ah, see? I did it again.)