Melody Carlson is my daughter's favorite author. She writes novels for teens, devotionals and children's books. The words seem to jump right off the page because her stories are so relevant. She speaks about situations that teens, young adults and women face every day. A reader can consider her stories in making sound decisions based on things her characters are going through.
Robin Jones Gunn is another wonderful author. One of her many series is the Christy Miller collection. This is, so far, a 4 Volume series. Each Volume is 3 books in 1. Christy faces so many situations from moving to a new city and entering high school, to evaluating various relationships. Through it all Christy does her best to listen to what God is telling her, and though growing up is hard, she finds comfort in the arms of her Savior.
Degrees of Betrayal is a trilogy written by 3 authors (Melody Carlson, Dandi Daley Mackall and Jeff Nesbit). Each book is based on the same event yet told from three different perspectives - each girl and a guy. Each character is dealing with the specific event, while dealing with what's going in their specific lives including their internal emotions. These books go deep under the surface of each character and shows that even though we might not want to see God in the midst, He is always there and His plan is always best.
These books make great suggested reading for your teen, give as a gift or enjoy yourself.