Who is Melinda Jeffers from Wake and what is their importance?

Melinda Jeffers is one of the most popular girls in school. Ever since they were 12, Melinda has been picking on Janie because of her clothes, hair and the way Janie looks. Melinda continues this behavior throughout high school. Since Melinda is friends with Carrie, however, Carrie tries to keep Melinda from being so cruel to Janie.