None. At fourteen our daughter could use foundation for cover up and clear lip gloss. And at fifteen she could add in mascara on top and a little blush. She looks neat and clean and can still see through her lashes unlike some girls I've seen at that age.
Something very light. Nothing that is too dramatic because that causes you to look old. Lip gloss, Some light eyeshadow and mascara should be perfect. Try eyeliner on the top lid for something a little bolder.