Birthdays come and go, and as each one arrives I usually embrace it with joy.

It is a reason to celebrate, to get together with friends and family and, if nothing else, the opportunity to justify that extra bit of cake.

I have never really worried about the number, and I wasn’t particularly bothered by the next one that arrives in a few weeks’ time.

That was until I realised what it really meant. Ticking a different box.

When it comes to surveys (and journalists) they love to know how old you are.

Under 21 is great, but then the surveys start to group you into categories that, like it or not, define whether you are young, not so young, middle aged, or older.

And I, dear reader, am about to move on.

It’s been a long time since I filled in a survey, but the box next to “46-60” beckons.

Ironically, the moment I realised this was when I went to stock up on some age-defying face serum.

I’ve been wearing the same product for years, and about this time, I stock up on a post-Christmas (use those vouchers), 3 for 2 offer.

The range has been treated to some new packaging, and I happened to glance at a leaflet giving people like me the idiot’s guide to which one was best for me.

And there it was, in black and white. I was about to move into the next age group. No more for me the anti-wrinkle advance formula, where there was still something to work with and attempt to smooth.

I was now on the cusp of The Next Level, where what little I have left needs to be plumped, brightened, tightened and lit up with everything they can throw it.

I’m not sure if I was looking for the honest answer or some hopeful flattery when I approached the sales assistant, clutching my products and asked: “Should I carry on with what I’ve been using or start using this one for more mature skin?”

“Oh, I’d go for the more advanced one,” she said. “It’s packed full of great stuff and you might as well get as much of the benefit as soon as you can.”

I know she meant it in the nicest possible way, but my heart sank as I realised that was the day I’d aged.

I told my husband, who helpfully reminded me that I was already nearer 50 than 40.

“Thanks for that,” I said. “You’re not helping.”

“I don’t know what you’ve got to worry about,” he replied. “Just wait until you realise that if you responded to those ads Michael Parkinson does, you qualify for a free pen. And the next girls’ ski holiday you go on, I could get away on my own with Saga.”