The Demi Moore photoshoot shows how prepping for the beach has changed since I was a teenager

How old were you when you first realised that shopping for a new swimming costume was a stressful event?

It’s the moment you leave behind those carefree sandcastle-building days of childhood, where pulling on a slip of brightly coloured Lycra was merely an inconvenience before you sploshed into the sea.

Probably for most of us it begins around puberty. We start to notice other people’s bodies. In real life. And in magazines. And begin to compare them to our own, usually with an unnecessarily critical eye.

My awkward teen years coincided with the rise of Baywatch, the Californian beach lifeguard show that launched Pamela Anderson and relaunched David Hasselhoff. Like millions of others I was glued to it every Saturday tea-time. I loved it. Years ago I had the theme tune as the ringtone on my phone for a while, and if someone called me on a train, half the other passengers would look up with a crooked smile on their faces, a pleasant memory dancing before them. Or perhaps running… in slow motion… along a beach… in a tight red swimsuit. I am not here to judge.

But however much Baywatch did for Anderson’s career, it did rather less for the confidence of teenage girls. This look, her look – long blonde hair, blue eyes, big boobs, tiny waist and legs that stretch to the centre of the earth – was very much presented as the ideal.

In the 1980s a new look for women emerged from California – it was ostensibly about health – lean, clean eating and Jane Fonda workouts. But really it was an aesthetic dream of a body so lean and aerobicised that there was no need to hide behind anything more than a piece of stretchy cloth. It was presented as something light and free, spontaneous, and more honest somehow than the tricks and corsetry of yore. And Pamela was the ultimate example.

Sales of red swimming costumes rocketed. I bought one myself. I went to the shop and tried it on over my jeans and T-shirt in a brightly-lit communal changing room. I took it home. I tried it on again in the privacy of my own bedroom, with the curtains closed and without my clothes. I did not look like Pamela Anderson. It was disappointing. I gave up on anything other than sensible black one-pieces from Marks and Spencer for the best part of twenty years.

Summer holidays are approaching and so once again we turn our attention to the perils of buying a new costume. But somehow these days it feels a lot less perilous. You can buy online for a start. And now the adverts are all about telling you that you look great however many lumps and bumps you have. Since the backlash against and subsequent banning of an ad for protein shakes in 2015, which featured a bikini-clad girl next to the words “Are you beach body ready?”, marketing teams have paid heed, and now it’s all softer and kinder.

Campaigns for a variety of products tend to feature a wider range of body shapes, ages, ethnicities. It’s less about feeling bad you don’t look like that, and more about feeling good you do look like this. It’s not just about what you’re wearing – it’s about who you are.

This new approach seems underlined by the recent campaign for international swimwear brand “Andie”. It features the 58-year-old Demi Moore and her three adult daughters. They drape across each other comfortably, or stand confidently looking at some far away point, as though what they are wearing is the very last thing on their minds. I like it.

Yes, of course they look good in the conventional sense, as we have been conditioned to understand it. Yes, the four of them possess bodies that less than 5 per cent of the population could ever achieve. But still, there is something a bit more self-possessed about them all, compared to the bikini ads of the past.

The atmosphere is not especially sexual. It’s not about being attractive. They don’t need your approval. Or mine. Any of them look like they could be mentally working on their doctorate whilst lying casually by the pool. I mean, they probably aren’t, but the main thing is they exude a sense of not caring what the observer thinks, and this is what I responded to.

And so I bought one of those swimsuits, online. It arrived and I tried it on. It didn’t make me look like Demi Moore. It made me look like me. And that’s fine. Now take me to the beach. I want to have some fun.