There are many milestones in a woman's life: The beginning of her monthly cycles. The day of her wedding. The birth of her first child. The day she spots her first wrinkle ...

Oh, mirror, mirror on the wall, why does it have to happen? We know we accumulate wisdom with the years, but must we also accumulate wrinkles? The sight of those tiny crinkles under our eyes or the first faint creases along our foreheads (not to mention the appearance of broken capillaries and age spots), can make us want to turn away from our own reflections (or, like the evil queen in Snow White, just smash the mirror).

Faced, so to speak, with less than youthful skin, we have two choices. We can accept it and make friends with our frown lines. Or we can fight it every step of the way.

Want to arm yourself for battle? We have considerable control over how our skin ages and plenty of ways to keep it glowing and youthfully smooth, ways that don't include weird facial exercises, skin creams with hundred dollar price tags, or trips to a plastic surgeon's office.

Even if you haven't yet spied that first wrinkle, you still have good reason to lavish your still youthful skin with TLC. "The earlier you start to care for your skin, the bigger the difference you'll see as you age," says Francesca J. Fusco, M.D., a dermatologist in New York City.

To achieve more youthful looking skin, it's important to understand how it changes through the years and why.

Why Skin Gives In

Obviously, aging alone takes its toll. Our skin's protective outside layer, the epidermis, becomes thinner and increasingly fragile. Oil glands produce less oil, leaving the skin drier and more sensitive. The number of blood vessels decreases, so you lose the rosy glow of youth. Moreover, aging slows down the speed at which you replace old cells with fresh, new ones.

Genetics, too, plays a role in how skin ages. Fair skinned women, for example, show signs of premature aging faster than women with darker skin. That's because fair skin contains less melanin, the substance that gives skin its pigment and helps protect it from the sun, explains Linda K. Franks, M.D., a dermatologist in New York City.

But that's only part of it. No matter how many candles may decorate your birthday cake or how fair your complexion is, to a large extent, your skin's "age" depends on how well you take care of it.

The cardinal skin sins are basking in the sun and smoking cigarettes. Both speed the breakdown of collagen and elastin, the structural proteins that give skin its youthful plumpness and ability to snap back. The result is premature sagging, wrinkles, roughness, age spots, and blotches. Other skin agers include chronic emotional stress, poor nutrition, excessive dieting, and drinking alcohol, says Debra jaliman, M.D., a dermatologist in New York City.