04/06/2014 06:40 BST | Updated 03/08/2014 06:59 BST

I'm Pregnant at 28 - and I Think Kirstie Allsopp's Right

A few weeks ago I was at a BBQ in Hackney, anchored to my seat by a very pregnant belly, discussing maternity leave with three self employed artists in their 30s. A look of shock swept over E's face, mid conversation: "I'm sorry," she said, "but I just can't believe you're having a baby."

"It's not Annie being pregnant that's weird, it's the fact that the rest of us aren't," said my 31-year-old sister.

The three of them are in long-term relationships and their boyfriends are keen to have children but they're all putting it off for the same reason: work. It certainly feels less secure taking time out from a freelance career than it does a permanent job, which offers maternity pay, leave and the option to return at some point.

But why, then, was I - a self employed writer - keen to become pregnant in my 20s and risk dropping behind my colleagues, as well as losing the full time contract I've been enjoying for the past year?

It's simple. I know that I can return to writing whenever I like; that my copy will improve with age, but that my fertility won't. And so I empathise with Kirstie Allsopp's feeling that women ought to prioritise having children during our fertile window.

Setting aside the futile comments about not all women wanting children, for those who do plan on having a family it's undoubtedly less complicated to conceive in your 20s than in your 30s. Yes, the media might scaremonger but the truth is this: we're born with a finite supply of eggs and once they're gone, they're gone.

That's why my mum decided to have her first child aged 29. She'd read that it would be easier to conceive before turning 30 so although she hadn't yet been to university, wasn't on a career path and my dad was in the middle of his degree, they got started. Nine months later my sister was born.

And of course it's not just egg supplies that deplete with age, it's also energy supplies. Having children younger means that you'll probably find it easier to run around after them and cope better with late nights. It also means younger grandparents, who might be able to help with childcare.

So my mum didn't ever regret their snap decision to start making a family in her late 20s. But she did find it difficult being judged by other women with degrees and careers and so she returned to higher education in her 50s to complete a BA in person-centred counselling, and is still practising now.

For my girlfriends, ranging in age from mid 20s to mid 30s, it's not just careers that stand in the way of reproduction; it's also letting go of their drink-fuelled social lives. They've all been to uni and most are working in jobs they love but they're not ready to put down the wine and pick up the nappies.

I can't help but wonder if it's a bit of a London thing. I moved to Somerset aged 24 to live with my then boyfriend. I was writing for the Western Gazette, trying to carve a freelance writing career out of the few opportunities available in the South West, and leading a fairly civilised existence of chickens-rearing, National Trust properties and bonfires in the garden.

Meanwhile, the friends I'd left in London were partying hard - with no signs of slowing, or settling, down. And so when we told them a year later that we were getting married, they were quite surprised. It wasn't what people in London were doing.

After two years in Somerset, we returned to the city for work and immediately got sucked back into the hedonism. But then I became pregnant. And so I've spent the past nine months sober, slightly envious as my friends tell tales of wild nights out, plans for travelling adventures and major career changes, but also quietly pleased that I got knocked up.

It feels backward to be telling girls to leave school, have a couple of babies and then think about careers, as this would mean total financial dependency on the children's father, or the government. But I definitely see Allsopp's point about keeping an eye on fertility and not being afraid to step off the career path for a year or two to start a family while it's still biologically feasible. That's what I'm doing, and I don't regret it at all.