I wouldn't say that there is a specific age when it's appropriate to wear foundation. I started wearin tinted moisturizer in high school. Then I used mineral foundation, then liquid. I think it's okay if your skin actually needs the coverage. If you don't have acne or blotchiness, there really isn't a need for it. Foundation does not hide facial hair. I recommend waxing facial hair. Bleaching facial hair is another option. Redness can be reduced by powder, concealer, or foundation.