With Madonna hitting her half-century, for the first time ever it's fashionable for a female to be 50.

Finally, a woman's experience and wisdom will be valued as much as having young, wrinkle-free skin ... Yeah right. And Melanie Griffith is ageing naturally.

Show me a woman who is happy with her age and I'll show you the electro-convulsive therapy scorch marks. As all women know, the secret of staying young is to eat only organic food, hit the sack early ... and to lie your head off about how old you are.

With my 50th birthday approaching, real panic set in. Turning 50 is the most nerve-racking event in a woman's life, well, which doesn't involve gynaecologists.

Men have mid-life crises all the time. (Mind you, the question on most women's lips is how can a man have a mid-life crisis when he's never left puberty?) If I were a man I'd simply buy a souped-up automobile as macho as it could get, without actually growing a penis as a hood ornament.

But how does a woman have a mid-life crisis? My first instinct is to make a lunge for the wine and peroxide bottles (what if I got them confused?) but, just as I was about to transmogrify into a demented Barbie wannabe, a spandex-wearing gym junkie with pores in need of constant rehydration, not happy unless squeezed into a double-zero dress and having whole conversations about seaweed facials and raspberry enemas, I realised that my reality cheque had bounced.

What does it matter if I'm turning 50, when I don't feel it? If I didn't have mirrors all over the house I'd think I was about 25. (Mirrors don't lie — but they can be shattered with that stiletto your teenage daughter says you're way too old for.)

Some of my girlfriends on the brink of 50 are so pessimistic they see the bad side of everything. If they had their way they would be skywriting “there's no such thing as Santa” over Euro Disney.

OK, my eyesight is getting a little blurry and my knees creak occasionally but that doesn't mean I must sit at home on Saturday nights tweezing stray facial hairs, discussing dietary fibre when it's not even breakfast and obsessing over whether or not my toothpaste has tartar control.
Not when there are so many things left to try. And, with the kids nearly off your hands, there'll be so much more time to try them. Riding an elephant, for example. Swimming with a dolphin. Sky-diving.

I've never seen the aurora borealis. Or a solar eclipse. I've never seriously taken up a musical instrument. I've never read Proust. Nor have I had sex in the broom cupboard of a leading London restaurant.

And what of all the wonders of the world I'm yet to glimpse? The Great Wall of China? The Taj Mahal? Machu Picchu in Peru? Brad Pitt naked. Admittedly, no man, let alone a cinematic love god, is going to want to get into your pants if even you can't. You're not going to attract anyone if you've given in to middle-age spread and your wardrobe consists of vast shirts bought to cover up wobbly bits and pedal pushers to hide bulgy knees and leg stubble.

Advice, like the flu, is better to give than to receive. But keeping fit physically is definitely the best way to feel youthful. As a writer, my job is sedentary. If I didn't exercise, I'd be so dog-like I'd be catching frisbees between my teeth and sniffing luggage at Heathrow.

To avoid this, I either swim a mile a day or run five kilometres. Most of my English girlfriends conquer the Great Indoors. Reading, leg-waxing and gossiping is about as aerobic as they get. They would only run if their flats were on fire.
But you don't have to join a gym to keep fit. If your idea of the Great Outdoors is the bit between Bond Street Tube and Selfridges, then make sure you use the department store stairs and not the lifts. It'll give new meaning to running up bills.

Be warned, though. Exercise is not glamorous. When you collide with the man of your dreams while covered in sweat, try to remind yourself that dignity is a superfluous emotion for mothers. Like styling mousse for bald men.
But any activity will do. As long as your preferred exercise isn't skipping — skipping breakfast, lunch and dinner. Anorexia will give you a figure to die for, literally. Exercising daily means you can basically eat what you like.
Pre-menopausal ageing angst increases your appetite enormously. My only criteria for dinner is that there be a lot of it. I am considering putting speed bumps in my kitchen to slow down my progress to the refrigerator. (It's not my fault. As any woman will tell you, stressed spelled backwards is “desserts”.)

Many of my girlfriends aren't getting older. They're getting injected twice a week with foetal lambs' brains. But I'm trying to resist resorting to a little shopping and tucking, and for any woman considering cosmetic surgery I have two
words: “Michael” and “Jackson”.

Experts assure us that Botox is safe, but that's what they said about silicone breast implants and then, later, soya. Perhaps that's why cosmetic surgeons wear those little green masks so that if anything goes wrong, they won't be recognised.
Apart from exercise, diet and good tailoring, without doubt the best way to stay youthful is to feel that way. Or, take the Joan Collins route and feel a youth. Joan's hubby, Percy, is 30 years younger, and when asked if she considered the age difference a serious concern, she replied with a sassy shrug: “If he dies, he dies.”

Perhaps birthdays are nature's way of telling a woman to get a toy boy? Why not think like Madonna and simply wear a micro-mini and dress for cleavage? You'll soon be spending the evening as the centre ornament of an arrangement of boyfriends, most of whom will be a head shorter than you in your high heels — and happy to be so. It may take a lot of bottle — preferably champagne — but what a way to celebrate your 50th birthday: a tequila-fuelled fandango with a toy boy till dawn.

But whatever way you choose to celebrate your 50th year, just remember this: you may only be young once but you can be immature for ever.

* Kathy Lette's latest novel, To Love, Honour and Betray — Till Divorce Us Do Part, is published by Transworld. Copyright Kathy Lette, 2008.

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