It means they're a classic girl in 2013.
And lot's of guys do this too nowadays (I still think it's dumb, but whatever).
The term 'attention wh0re' is overused here, IMO. We all have varying degrees of attention wh0rdom within us, it just tends to shine brighter with girls (and unbearably so with some).
PS: I'll admit, I first typed 2012 up there, and had to go back and change it.