You can take classes, use the best equipment, but in the end what you really need is talent. And Talent does not wait till you are mature or experienced. As evidenced by the pictures submitted to the National Geographic Kids International Photo Contest.
If you want to incorporate photography into your homeschool or just want to let your kids express themselves you don't need to buy them an expensive camera. Virtually all mp3 players and phones come with them these days. If you are studying art suggesting subject matter might get them started, or themes. Have them play with the settings, try it in sepia. Have them look at things in a different way, from up high or upside down. Its really marveling to see things from a child's point of view.
Here are some my kids have taken, to give your kids an idea.