
I kinda get where Ibeline is coming from. She's lived her entire life in a world that was literally created for her. (At least that's what it seems like the author of the novel did) I don't think she means to be a bitch, it's just that her entire reality is changing around her and she has no idea how to react or adapt to the situation. She's not your typical attention whore, she doesn't seem like she necessarily wants Arwins attention she just expects it because that's how the world had worked up until that point.
I don't think how she's reacting is right, but I can kind of see why someone would react that way. Plus it doesn't seem like she's actually done anything bad to Latte, at least not yet.