I'd go with Markus Zusak "The Book Thief". The book is set in Nazi Germany from 1939-1943 and is about a foster girl, whose real parents were taken away due to their political views. Throughout the book she realises that the things that the Nazi regime is saying about the Jewish population is untrue as she meets a Jew and forms a remarkable friendship with him. She realises that everything that people in power say isn't true, so in that way she matures.