Ruby Nightingale Her first adventure

Ruby Nightingale is 13 years old, a bright girl, who much to her distaste, is sent off to boarding school. She finds a mysterious book, where she can go into any story she chooses, but she has to play as a certain character. If she messes up the plot, the story could be completely changed forever. One night she decides to go into a story, messes up part of the plot, and she has to change it before it's too late. Will she be able to?