In what way does Simone demonstrate a sizable shift in her confidence level in Chapter 19?

In Chapter 19, while the class is waiting for the tardy Mr. Piper to return from lunch, Tia suddenly turns around in her chair and looks fixedly at Amal. She then starts talking about an article she read about female circumcision and asks Amal loudly, "So are you, you know, whole down there?" (172) Simone demonstrates a newfound lack of bravery and self-confidence when she stands up for her friend Amal and tells Tia to shut up.