This week, the Guardian told me to turn up at their offices with my rucksack and talk to a lady. It'll be great, they said, you can talk about feminism and fashion, and because I love the Guardian, I obeyed. The resultant jolly interview, in which I look and sound precisely as baffled and overwhelmed as I was by the whole affair whilst trying to jam in some points about Marxism, gender and consumerism, can be read on the paper's homesite. I have been trying to put my finger on quite what it was about the experience itself that put me so very far outside my comfort zone, and it is this: I just felt scruffy.

I was asked along to make a case about shopping and the banality of consumer choice as a model of empowerment. Justine Picardie, my fellow interviewee, said lots of interesting things about Chanel as an icon and how empowering fashion can be, and I suddenly felt terribly unglamorous, as I usually do in 'proper media' situations. Sitting in those shiny offices, with my ripped grey dress and straggly dyed hair, I found myself, all at once, anxious to prove that just because I believe, with all my heart, that there is more to a woman's life than how she looks and what she buys, that doesn't mean I'm not light-hearted, not fun, not a proper girl. That tension is such an important one in the way we talk and think about feminism.

The thing is that these things do matter; fashion, consumerism and style matter, they matter to women in particular because we fritter away so much of our time and energy and money, whether we want to or not, trying to negotiate those boundaries of gender and status that are mediated through clothes, hair, shoes, makeup, bags, accessories. These are the ways that we prove we are good women, good shoppers, people who know how to conform and consume and seduce, people who want to please, to fit in, no matter how complicated the rules or how high the stakes. Not for nothing are feminists so often stereotyped as ugly, unfeminine, shaven-headed, androgynously dressed. To want any type of power other than the power to seduce, to please, to entertain and comfort and excite is to forfeit one's womanhood on some vital aesthetic level.

Consumer feminism only condones the latter kind of empowerment, and it is a mitigated type of power, and it is not the same thing as control. If you want a vision of a future for feminism, imagine a high heel coming down on a woman's face, forever. At the same time, a vision of a future without dressing up would be a dull feminist utopia indeed.

This has been on my mind lately, because I'm in the middle of a process of what my mother calls 'smartening up'. This involves gradually easing away from my former aesthetic of shaved-head-and-baggy-black-cyber-gear - a hangover from the days when I used to work in a shop in Camden Market- and trying to accustom myself to the niceties of hairstyles, handbags and clothes that don't give the impression, at various meetings, that I've been up all night at the sort of club where they sell pink drinks to teenagers to stop them chewing off the insides of their own mouths. I am finding the whole process confusing, upsetting and expensive.

I've always been fascinated and infuriated by the way that one is obliged, as a woman, to purchase the trappings of one's own gender, and infuriated by the way the rules keep changing the deeper into the game you go. I've been getting into more and more professional situations where it is no longer okay to turn up with huge biker boots and a slash of clashing lipstick and expect to be taken seriously. As women, everything we wear is a statement, and we have no right to remain sartorially silent. We negotiate a field of signifiers every time we open our wardrobes, or, in my case, every time we rummage through the clothes-pile on the bedroom floor.

Two weeks ago, I stayed with an impossibly glamorous friend who insisted upon dressing me up in her latest acquisition, an Alexander McQueen gown. I had never seen such a beautiful piece of clothing in my life, much less tried one on, but when she eventually persuaded me to do so, I stumbled out of her bathroom feeling like an animated doll, banging into things, blinking in uncomfortable confusion. I was afraid to sit down in the thing in case I damaged it. I was afraid to look in the mirror, in case I liked what I saw, and in case that mattered, but my friend made me look. And what I saw, underneath the gorgeous tailoring, the elaborate hairdo and the makeup, was a girl in battle armour.

"McQueen said the clothes he made were supposed to be armour for women," said my friend, taking a picture. Armour is just what that impossible dress was. Wearing it, I felt like a conscript in a war that I hadn't signed up for, a war that had almost nothing to do with fun. The simple joy and play of dressing up and experimenting with clothes and style seems so fraught with anxiety that I am beginning to wonder if we can ever start to reclaim it. Girl armour does give you power, but it comes at a cost.