What does Mattie Cook look like in Fever 1793?

In "Fever 1793" by Laurie Halse Anderson, Mattie Cook is described as a fourteen-year-old girl with a strong and determined demeanor. She has dark hair, often tied back, and is depicted as being of average height for her age, with a slender build. Her character embodies resilience and a sense of responsibility, reflecting the challenges she faces during the yellow fever epidemic in Philadelphia.