Ruby Red, by Kerstin Gier
Kerstin Gier wrote an impressive first book to her Ruby Trilogy. Over the centuries Gwen's family has kept a secret. They are part of team of time travelers who are working to solve a very old puzzle. Gwen thinks she is a common 16 year old girl. Her cousin is the one destined to be special. Charlotte was trained her entire life to be ready for when it was her turn to travel through time. Yet, the family was wrong. It wasn't Charlotte who trips into the past but instead it was Gwen. One minute she's heading out to the store for sweets, the next minute the scene changes. Gwen couldn't believe she can travel back in time. Her family is quite upset to find out that she is the magical Ruby that they have been waiting for.