I do think it's going to turn out that her parents are bad and she's having trouble with problematic guy relationships and she's screwed up on the inside and all that jazz. And I won't go so far as to say I don't give a damn. But whatever her situation is, it would probably be a lot better if she hadn't adopted a strategy of deliberate worthlessness.
And as a reader, knowing that the writer is going to busily turn around the initial impression and try to redeem her just makes me more annoyed, really. I wouldn't mind having an annoying character so much if I didn't think the mangaka was about to tell me "No, you can't consider her annoying because we're shaping the plot that way" when sorry, she's bloody annoying and nothing the storyteller can do is really going to fix that.
To me she stinks of "Progress is moving too fast, editor thinks we need to stall, so add a random character to create some complications". And for me that's an unnecessary story approach anyway. Assuming we have 2X chapters left, I would much rather spend X chapters getting to the confession and then X chapters on nice relationship stuff, than X chapters on complications with annoying side character and then X chapters getting to the confession, the end.