:grouphug:
The Amy Welborn's books are wonderful, and Catholic! Some of C.S. Lewis's Mere Christianity might also be appropriate. But more important than reading a book, no matter how good, is discussing your beliefs. I've been in a similar position to your daughter, although I was coming from an agnostic/nominally Christian family. I found myself believing in God, but kept thinking "How can smart people believe in Him? Have I lost my mind?" In the end, I found that there are logical, compelling reasons to believe. My kids have asked hard questions too. Answering can be so difficult, but if we want our children to be strong in their faith, we must answer their questions.
I encourage you and your Dh to have some good discussions with your DD. They will be difficult, but I'm sure they will be rewarding for both you and her. :grouphug: