Alexa Chung: 'Now I'm 25, the only shoes I can look forward to are slippers'

The perceived age of celebrities is something I have become increasingly interested in over the last couple of years. I'm sure nothing is more irritating than hearing a young person talk about getting old, but if I don't, there won't be a column this week because it's been bothering me for a while now.

I have never lied about my age, and two weeks ago I... turned 25. There, I've said it. Sometimes, I think I'm the only person in my profession who is being honest about their age.

I was pleased to reach 25, if only because, when I was at school, I longed to own a pair of knee-high boots. Upon voicing this desire, somebody kindly informed me that knee-high boots, could ONLY be carried off from the age of 25. It is somewhat disconcerting to think that I took fashion advice from somebody I had probably only ever seen in a standard-issue school uniform, or, at a push, a PE kit, but still, it's something to which I have stoically adhered to. The question is, now that I am the right age to rock a knee-high boot, what type of shoe do I have to look forward to other than slippers? Here the panic sets in.

At 24, I began to worry that perhaps I should have been a little more frugal with the truth when I graduated from modelling to the dizzy heights of youth-TV presenting. And therein lies the problem: "youth TV" the term implies my retirement is imminent, it tells me it's quite possible that I'll be shoeless and jobless by the time I'm 26. Quelle dommage! I appear to have a knack for choosing careers in which 30-year-olds are rendered veterans. Given the media's disdain for the old, you can see why some people in the spotlight resort to fallacy in order to remain a certain age.

The tabloids a couple of weeks back were again reporting that Sarah Harding had been out partying and, shock horror, getting drunk, this time to celebrate her 27th birthday. I have a couple of issues with this story: firstly it's not news, and secondly it's not true. OK, it is true, she is 27 (Wikipedia told me, so it must be true), and probably some people are interested in what she got up to that night, including my brothers, and myself because I'm a massive Girls Aloud fan, but I'm suspicious because 27, in my mind, is the age of a liar. It's the age most Hollywood actresses remain frozen at (their botoxed faces, too) for decades at a time.

There are exceptions to the rule. An uncanny number of famous people top themselves at 27 – the last bastion of youth. It's the rock'n'roll age to die: Hendrix, Joplin, Cobain – they lived fast, died young.

Their eternal youth makes my preparations for old age – including deliberating over whether or not to invest in property in Shoreditch and arranging a pension with my financial advisor – seem all the more dull.

But there are of aspects to growing old which do appeal to me. I'm simply allowing myself to be brainwashed by the consensus these days that life beyond 40 sucks. But why? Personally, I love warm jumpers in sensible colours, I cite the Queen and her love of Barbour as a style inspiration, I'd like to spend my days reading a library of books and I happen to find beachside strolls rather fulfilling. I'm particularly looking forward to being old enough to sit in a corner at Christmas time, in MY chair, making completely out-of-order comments to my family that they'll have to accept because I'm ancient and, probably, senile.

When my parents arrived at my house this week to deliver belated birthday gifts, I was surprisingly happy to discover that one of them was a hand-held blender. I began to imagine how I could make well-blended soup and invite friends over to marvel at my culinary skill. But then I realised that staying in is for old people and actually it was probably far easier to meet my friends at Bungalow 8 for a whiskey.