I read this as a teenager and it changed my life. I am an imperfect and sinful person, but God has never made it more clear to me how much He understands us than through the words of this book outside of His Word.
If you find yourself insecure, anxious, afraid, rejected, broken hearted, depressed, bitter or angry, lonely, overwhelmed by life and everything else around you and inside you, this book is for you. You only know how beautiful you are to the Father, when you get to know his heart and learn that he is delighted with you.