The 'Elixir' series by Hilary Duff is generally suitable for young readers. It has themes that are appealing to a younger audience such as first love and self - discovery. However, there are some elements of the supernatural and mild danger which add an exciting edge.
I'm not sure if there are a huge number of novels directly by Hilary Duff. However, 'Elixir' stands out. It has an engaging plot that takes readers on a journey through a world where the normal and the paranormal collide. It's a great read for those who like young adult fiction with a touch of the otherworldly.
Hilary Duff was approximately 16 at that time. Her performance in the movie was charming and memorable. Her age added to the youthful and romantic essence of the story.