You're health is very important. When I am shooting a film, I am on location 12 hours a day. My advice to aspiring young filmmakers is to never abandon your goal no matter how tough the journey is. Life is competition. Be very patient, be organized and plan ahead.
Creativity has no age limit.
Practice shooting on a video camera. When you're on a family vacation or at a birthday party, take the initiative to be the cameraperson. That's how you can start training your eyes to visually compose scenes. A director has to know how to visually tell a story. You're never too young to think like a filmmaker.