'My son's girlfriend is basically perfect in every way. But she's the same age as me.'

When my son told me he'd met someone, I was thrilled. Finally. After years of watching him flirt his way through a small postcode's worth of girlfriends, he sounded… different.

"She's amazing, Mum. Just… different."

I've always liked the girls he's brought home. Sweet, polite, wide-eyed things who called me "Mrs," and looked at him like he hung the moon. Lovely girls who'd stay for a few weeks or months, help me clear the table, then vanish quietly once things fizzled out.

It was a bit of a revolving door, if I'm honest. I never worried too much, he was young, charming, and I'd raised him to treat people well. My only lectures were about being respectful and safe. I never once thought I'd have to talk to him about falling deeply in love.

Until Kiera*.

Even before I met her, I knew something was different. The way he talked about her, it was slower, softer, like she was something precious.

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The first time I met her, I was in activewear, hair scraped up, standing at the fridge eating sun-dried tomatoes straight from the jar like an animal.

She was beautiful. Effortlessly beautiful. The kind of woman who makes you instantly aware of how long you've been wearing the same sports bra. She had perfect skin, glossy hair, and that calm, self-assured confidence that comes with knowing exactly who you are.

My son, usually all swagger and sarcasm, was suddenly fidgety and polite. They were heading to an art gallery — an art gallery — and I couldn't help teasing him.

When they left, I caught my reflection on the glass door: tired face, tomato-oil-stained shirt, messy bun.

"Oh to be young again," I thought, then immediately rolled my eyes at myself.

It was a few weeks before I saw her again. My son barely came home, he was always at her place, cooking dinners, going to exhibitions, doing things that made him sound like someone else entirely. When I finally convinced him to bring her to a family barbecue, I was excited.

She arrived carrying a bottle of wine, instantly lighting up the backyard. My brothers exchanged impressed looks, my mum whispered, "She's gorgeous," and within minutes she had everyone laughing.

You couldn't not like her. She was engaging, smart, funny. The kind of woman who somehow makes you feel interesting.

Over lunch, we started chatting about travel. She'd just been to Bali with her friends, and was already planning the next trip. I listened, smiling, imagining how nice it must be to still have that kind of freedom.

Then she said, "Next year we're doing a big one, a joint 40th in Bali with my girlfriends. Big villa, DJ, the works."

I froze.

"Your 40th?" I asked, trying to sound casual.

She smiled. "Yeah, I just turned 39 last month."

I laughed, but it came out strained. "Wow! You don't look it."

And then I wanted to die.

Because she went right on chatting, blissfully unaware that my brain had just imploded.

40.

She's 39. I'm 42.

My son's girlfriend is three years younger than me.

For a few seconds, everything went muffled. The world tilted a little. It wasn't just that she was too old for him… it was kind of more that she was too close to me.

For the rest of the afternoon my mum and sisters-in-law whispered about the age gap, desperate to know what I was thinking. There was a silent "WTF" hanging in the air. I was spinning.

Later that night, after everyone had gone home, I poured a glass of wine and sat on the couch trying to unpack the strange, uncomfortable feeling pulsing through me.

I wasn't judging. I wasn't even disapproving. I was just… rattled.

I knew what I should have been thinking about the practical stuff. The logistics. What dating a woman that much older might mean for his future. Kids, ageing, how their lives might line up years down the track. What people would say. Whether he'd be ready for the kind of baggage that comes with experience. But I couldn't go there. I'm not that kind of person.

Maybe because of what I went through when I got pregnant so young, I learnt early on that judging someone else's choices is a luxury for people who've never had to defend their own.

For years, I've said, "Age is just a number," and I believed it. Turns out, I only believed it when that number wasn't breathing down my neck.

When I had my son at 20, I was the youngest mum in every room. The one at baby classes with her own mum instead of a husband. The one people whispered about "such a shame, so young."

It took years to shake that off. By my thirties, I was married and with two more kids, and I'd finally found peace with who I was.

And then suddenly, at a family barbecue, I was thrown right back into that feeling of not fitting anywhere.

Kiera didn't make me feel old. She made me notice that I was ageing. Every fine line, every stretch mark, every bit of exhaustion — all of it felt like it was being reflected back at me in 4K.

I hated myself for thinking about it. I'm not that person. I don't compete with other women, especially not women my son is dating. But the thought came anyway.

What if she looks at me and sees "mum"? What if she compares us?

And then the ugliest thought of all: if she wasn't with my son, I'd probably want to be her.

I told my best friend the next day. She laughed and said, "Oh my god, that's wild, at least he's got taste." I laughed too, but my stomach flipped. Because under the humour was shame.

I scrolled through Kiera's Instagram that night, because, of course, I did. Bali sunsets. Aperol spritzes. Linen outfits. She glowed. I sat there in my dressing gown with a half-eaten toastie, feeling ancient.

But over the next few weeks, something shifted.

It wasn't about her. It was about me. Kiera had just held up a mirror, and I didn't like what I saw. Not because of wrinkles or age, but because I realised how much of myself I'd let fade into the background of everyone else's life.

She reminded me that 40 isn't a finish line. That women my age can still be magnetic, spontaneous, alive.

When she came for dinner again, she brought dessert, helped with the dishes, made my youngest laugh until he hiccupped. My son watched her with pure adoration. And I realised this wasn't a crisis. It was a wake-up call.

If he doesn't care about the number, why should I?

So yes, his girlfriend is my age. And maybe that's not something to be embarrassed about.

Maybe it's proof that I raised a son who sees women for who they are, not how old they are.

*Name has been changed due to privacy.

The author of this story is known to Mamamia but remained anonymous for privacy purposes.

Feature image: Getty. (Stock image for illustrative purposes).