Things like fine lines, sagging, and thinning skin are a natural part of the aging process. It’ll happen to all of us at some point in time. The concern, however, is that these changes will start showing up before they’re due, or what we call, “premature aging.” While there’s no set number to differentiate between “aging” and “premature aging”—crepey skin in your 20s or 30s typically falls into the latter category.