“Youth is wasted on the young,” George Bernard Shaw once said.

True or not, a youthful appearance certain-ly is more cherished among people who are — well, less young. Though fashion magazines and makeover shows imply that the Fountain of Youth actually is a syringe filled with Botox, there are many ways to defy the aging process without medical intervention.

Signs of aging are not limited to the over-30 set.

In fact, it is the habits that are established in adolescence that determine how quickly a person ages. And the sooner good habits are acquired, the more likely an age revelation down the road will elicit gasps of admiration.

Who — man or woman — wouldn’t like to hear someone say, “Really. You’re 40? You must be kidding — you can’t be more than 31.” Here’s how to get started:

• Avoid the sun. No one, male or female, should leave the house without sunblock of at least SPF 15.

• Moisturize. Skin dries out as it ages, so moisturizing your face on a daily basis will help prevent premature wrinkles and fine lines.

• Don’t smoke. At all. It leeches all the moisture from skin and leads to early wrinkling, especially around the mouth.

• Drink lots of water. Hydration prevents the shriveled look.

• Get lots of sleep. Sleep-deprived people are cranky people who frown a lot. It’s no secret that frowning leads to wrinkles.

• Eat sensibly. This doesn’t have to be difficult. There’s a direct link between eating too much sugar and too many highly re-fined foods and having prematurely wrinkled, sagging skin. Stick to lots of fruits, vegetables, low-fat or lean protein and whole grains.

• Eat reasonably. Portion control is a magic piece of the anti-aging puzzle, since excess weight can add years to your face. Restau-rant servings and oversized dinner plates have tripled portion expectations. Fight back by serving meals on dessert/appetizer plates; the meat portion should be about the size of a deck of cards, the pasta or rice about the size of a tennis ball.

• Get moving. The best way to stave off aging is to keep fit and flexible. Select a fitness regimen that’s easy to stick to re-gardless of climate. Home exercise equipment is a sound investment for those who are committed to staying fit. Some equipment is even specifically designed for the home. Newer treadmills offer user-ad-justable shock absorption to mimic running on various surfaces, and their design is as sleek as an Italian leather sofa, so they can reside in the den without disturbing the feng shui.

And speaking of feng shui, the final key to aging gracefully is a sense of serenity. Finding a spiritual center or place of peace will reduce stress and fill the half-full glass to overflowing. While yoga, meditation and other Eastern philosophies are well-known for their calming benefits, it’s also easy to find peace through simple actions such as a walk in the park, a warm bath or just sitting and staring out the window. Blood pressure slows, brows unfurrow — and aging becomes something that happens to other people.