Avengers: Age of Ultron Pietro and Wanda Maximoff

You know the story of Pietro and Wanda Maximoff, but what about Esther Maximoff? Esther was also part of Hydra's experimenting, she is 5 years younger and has two fiercely protective older siblings willing to die for her. What will happen when she trails her older brother and sister who are following in Ultron's lead? Will she use her powers for Ultron, or will she switch sides to help the Avengers?

Note: obviously I don't own the Avengers movies or comics
Also, this will be based on the movie - Avengers: Age of Ultron - sorry I haven't read the comic books!