A DOCTOR thought I was 38 last week. This would be fine except that I am 28.

Actually by the time you read this I will be 29. Birthdays are always a time of reflection. And lately my reflection has told a sorry story. In panic overdrive, I asked a friend how old I looked in my photo on this page. "A youthful 40" was the reply.

OK, I feel about 90. But I'm too young to have a facelift and I'm already thin. I have no grey hair and few wrinkles. How can I look so old? The answer, it seems, may lie in my permagrumpy expression.

In circumstances too strange to relate I found myself recently at a Suzi Quatro concert. What struck me more than anything was that Suzi (48) had aged far better than most of her audience. Not so much because of body shapes and number of wrinkles as behaviour and attitude.

It takes a gutsy girl to wear a tight black leather catsuit on stage aged nearly 50, but I had to hand it to her. Suzi carried it off.

"I made a decision," she said. "I said to the band I'll keep wearing this as long as I still get cheers for my ass." Duly when Suzi turned around with a coy look, only slightly tongue in butt-cheek, the audience went wild. "I guess I'm OK for another year," she joked.

Suzi meditates, does yoga and slow jogging. She hasn't had a facelift. She eats well, doesn't over-drink, sleeps well, all the usual stuff. But that was not what singled her out. There were more size 8 women in the audience. It didn't stop them looking tired and middle-aged. What made Suzi seem younger was energy.

"I've always had a lot of energy," she explained to me afterwards. "But I suppose I keep young by enjoying my life. By having balance. Enjoying my family and feeling lucky with my life. By making sure that everything I do is what I want to do. I think the catsuit still works. I like wearing it."

Energy is crucial to staying youthful, says Dan Hartley, voice and body language coach. "If you want to look younger, be younger. Watch how you walk. Do you bounce along like an enthusiastic child, or slope around, back hunched like an OAP? Posture is very important. Gesticulating a lot, smiling - especially when you feel old and tired - can take 10 years off instantly. Most people walk around with a world-weary expression on their faces that accentuates the sag and wrinkles."

Your look can also make a difference. Looser hair is more youthful. Unmoving hair is old. And of course you don't have to start wearing mature clothes.

But there is a fine line between still dressing young and looking a prat. Even Vogue fashion director, Lucinda Chambers, has fretted. "I am nearly 40 but I really like the idea of hair extensions. But then I thought, am I too old, is it undignified? I decided I wasn't. It can look terrible if you're wearing a mini-skirt at 50. I wouldn't necessarily do it but it could look great. Ageing itself is not the problem. Ageing can be sexy and sophisticated. Helen Mirren is the classic example."

Look younger for free

1. Don't wear more make-up just because you have more lines.

2. Don't automatically highlight grey hair. This can make you look like a middle-aged person who's highlighted their hair.

3. Do fun, spontaneous things that keep up your enthusiasm.

4. Revisit adolescent image obsession - check yourself out when walking past mirrors.

5. Be silly. Immature. Especially in professional moments. You may lose respect but at least you'll look young at the Job Centre.