What interaction does Nadira have with her sister at school in Section 5: Chapter 6? How does she feel about it?

Strangely, Aisha invites Nadira to sit with her perfect friends at lunch, and the girls talk about college, confused that Aisha applied to McGill in Canada. When Aisha tells Nadira she has been nominated for valedictorian, Nadira tells her sister it does not matter since she is not even going to college, feeling a strange, pleasant power by making Aisha cry for the first time.