Why is elizabeth the protagonist in Pride and Prejudice?

Elizabeth changes because at first she is prejudiced against Darcy, considering a stuck up, spoiled, rich bratElizabeth learns not to trust her initial impressions of peopleElizabeth learns this by seeing how people do things that are contrary to her opinions of themElizabeth is proud; however, it is her prejudice which serves as her main vice. Prejudice prevents Elizabeth from seeing people for whom they really are.