The easy answer to that question is that Illinois has a law that says anyone 13 or younger must wear a PFD when underway on a boat.
Many states have similar laws.
But, Christa, what we like to do here is explore the questions so that you learn the reasons behind the laws and regulations. When you understand how important it is to wear your PFD, we think you'll always wear it whether you HAVE to or not. PFDs keep you floating. Even if you are a good swimmer, a PFD helps you avoid getting too tired to swim. If you should hit your head or lose consciousness, a PFD can make all the difference.