Who is Charity Wharton from The Cupcake Queen and what is their importance?

Fourteen-year-old, Charity Wharton is the girl having the birthday party that Penny is helping to set up for. She immediately blames Penny and her mother when there is a disaster with the refreshment table at the party. From this point on, Charity leads the group of girls that bully and pull pranks on Penny. Charity also has a crush on Marcus.