Well I started when I turned 13, nothing but light lipstick and blush. Though I stopped after that, because it bothered me.
Now I'm 15 and I only wear eyeliner, occasionally.
Though makeup can make you look pretty, keep in mind that it's not very healthy to wear makeup at a young age.
I tried it at 14. It depends on you though.
Wait, you don't need it. Too many young girls put way too much importance on it. There are more important things to deal with at your age than wearing make up.
Depends on you. I'd say when you're under the age of 14, stick to lip glass and light, natural colors. And after that, slowly get into eye shadow and all. But remember that make up is to enhance your natural beauty, and not to MAKE you beautiful. You're beautiful already. Don't depend on make up :)
I'd say 16.