Uh - She might have been competition for her brothers' attention - but certainly not Harry's and I very much hope she is far more interested in that kind of attention from him.
To see how she deals with competition, look at the Easter Egg scene again: Harry seems upset, she confronts him, and tells him that he could still approach Cho. It seems she's more interested in Harry being happy, than being happy with her.
She's really not all bad ;-)