If someone were to squint all the time starting at 15 how long would it take to develop wrinkles?

It depends: It all depends on the health and thickness of your eyelid skin. Dry, thin or fair skin could develop wrinkles by the early to mid twenties. Moisturizer, sunscreen, a balanced healthy diet with plenty of omega-3 fatty acids, adequate sleep, and not smoking help to delay onset of facial wrinkles. Also try not to squint! wear glasses or contact lenses instead, if you need them to see clearly.

Nobody knows: I am not concern about when the wrinkles will develop but I am curious why you squint all the time. If you squint to see, it suggests that you may need glasses. Go to see an eye care professionals and have your eyes checked.