I think being jealous of Draco was the first really silly thing. But before, in Taboo Tradeoffs, she was only a damsel in distress. And before that she was the protagonist in Self Actualization, and that whole story-arc was pretty silly.

I don't think that she is very silly. Things like thinking that, going to McGonagall is the responsible thing to do, seem silly, but only in comparison to Harry. But if she doesn't start doing things that are relevant, soon, she will seem pretty pathetic. (Her actions in SA weren't relevant, and in Taboo Tradeoffs it wasn't really her actions).