"A middle-aged woman who drives a people carrier." I heard the words uttered, saw the look out of the corner of my eye, and slowly tuned into the pregnant pause that had interrupted our news conference. But it still took a moment or three for the penny to drop and realise my friend and colleague was referring to me. The complete cheek!

I was instantly offended by the description which obviously bore no relation to me - apart from the car. Then I saw that twinkle in his eye and mischievous smile, and I played along, feigning mock indignation. My colleague was in wind-up mode; he's not far behind me after all, age wise, and must know he won't look like the Milky Bar kid forever. I forced a chortle, but my modest ego felt slightly bruised by the joke, especially when some (older) people genuinely questioned why I was offended.

Having just nudged over into the forties, I don't feel like I'm ready to be put on the 'middle-aged' shelf just yet.

Getting old doesn't bother some people, and I would usually put myself in that camp, possibly because I haven't yet been afflicted by the onslaught of grey (I pulled out the one and only wiry white hair my husband pointed out last Valentine's Day). But I object to being defined by age. That "middle aged woman in the people carrier" sounds frumpy, dawdling in life's slow lane and far closer to pension age than I am. It paints a picture of someone I'm not.

In my mind I'm still the person I was when I was 20, even if that was half a lifetime ago. Admittedly my mode of transport then was a European rail pass, valid for a month at least, during which I spent many a night sleeping in station waiting rooms or on overnight slow trains to save money, even if it meant getting robbed in my sleep, losing my beloved camera, travel fork and journal.

I also liked noisy bars back then, went clubbing into the early hours, drank fizzy wine made from pears for £1 a bottle from Kwik Save and had no qualms about wolfing down half a pavlova with my housemate as a Friday night treat. Ah the glamour.

In all fairness I have grown up a bit since then. It's true I do now drive a people carrier. I also do the odd jigsaw, am a paid-up member of the National Trust, prefer pubs quiet enough in which to hold a conversation, choose quality over quantity when it comes to wine, and a lazy soak in the bath is the epitome of bliss.

My dictionary states middle aged is "the period of life between youth and old age, usually (in man) considered to occur approximately between the ages of 40 and 60". That's me then, but only by a smidgen.

However, according to a survey of 2000 adults, commissioned by York-based healthcare provider Benenden in 2013, middle age now is more about your state of mind than a specific age.

In a tick list, they highlight 40 points that suggest you are middle aged which include: if you enjoy afternoon naps (who doesn't?), moan when you bend over, are frustrated by modern technology, choose comfort over style when it comes to clothing (shoes, maybe) and prefer a night in rather than a night out.

From that same list I score on the following: I don't remember the name of many modern bands, but then music's never really been my thing, I moved over from Radio 1 to Radio 2 a long time ago, I know my alcohol limit, I think teachers all look really young (probably because they are), I'm partial to a games night in, and I take a flask of coffee on a day out.

But the list and I go our separate ways on other points; I haven't lost my way with tablets and other gadgets, I don't forget people's names, I haven't booked onto a cruise, I don't have a keen interest in the Antiques Road Show, and I have never listened to The Archers (though I'm sure it's very good). I am also not obsessed with my garden, yet, although I've become strangely fascinated by the dozens of tadpoles we're nurturing after rescuing them from a muddy puddle.

So, in the grand scheme of life, I feel I've steered clear of that frumpy old pigeon hole for a while longer yet - but when I do fall in, I'm confident the Milky Bar Kid will be there keeping me company.