Who is Sherry from A Map of the World and what is their importance?

Sherry is incarcerated in the same unit as Alice Goodwin, convicted on a charge of armed robbery for a crime in which she was an accomplice. She is 19 years old, very tall (six feet), has deep, glistening black skin, and orange hair that she wears in wears in a ponytail. Sherry had a troubled childhood and is the mother of three children.