Sometimes, the message overpowers the intense subject matter
Personally, I think the rating 15+ is a little but of an overreaction, the book while at times is mature, really conveys a powerful journey. It shows the hardships and downfalls that occurred during this journey as well as the happiness and joy that he earned as well. I think this book shouldn't be judged as to whom may read it solely based on age. I think it depends completely on maturity.