Oh, goodness! If you are sixteen, I can guarantee you this neither a "wrinkle" nor anything to be worried about. Some people really do have natural lines, which aren't wrinkles but creases on their foreheads and beside their mouths. I always did. And it looks just fine, really! I remember my gorgeous cousin having a couple of forehead marks and freaking a little at your age, but obviously no one noticed it and only she was concerned.
If your skin is particularly dry-feeling, though, it could not hurt to moisturize your skin with something gentle, like a Nutrogena product. But really, don't worry about that! And don't invest in wrinkle creams!