(Purely metaphorical, you understand: my abdomen is of the pasty, undulating type rather than the bronzed washboard variety so it doesn't tend to be available for general scrutiny.) The reason for today's philosophical bent is not just because it's Mother's Day tomorrow, but also because Harriet's 18th birthday is on Saturday. So, as she is the youngest, this means I will soon be the mother of adults rather than of children and therefore - I tell myself melodramatically - this will be my Last True Mother's Day.

"What is the point of me now?" I said mournfully to Mr Young this morning. He sighed heavily. (He does that far too often these days. I don't like it. It reminds me of my old maths teacher, Mr Clark, who got so used to sighing heavily whenever he had to explain something to me in lessons that he even used to do it when we passed in the school corridor.)

"What?" he said - clearly exasperated - "I do wish you wouldn't suddenly include me in conversations that you've just been having in your head. I haven't a clue what you're talking about."

I explained the reason for my low spirits.

"Don't be ridiculous," he said. (This too brought Mr Clark vividly to mind, either brandishing my maths homework or staring at me in disbelief as I stuttered my way through some algebraic problem.) "You don't stop being a mother just because your children have reached adulthood. As usual, you're just looking for an excuse to be a drama queen and weep pathetically over the baby photos." Very unfair. Although uncannily accurate.

Thursday

Archie's first puppy socialisation class. There are four others: a collie, a staffy, a labrador and a westie. They bark frantically at each other from different corners of the room, straining wildly at their little leashes while, above the din, the veterinary nurse bellows information about cleaning ears and clipping claws. Eventually, we are allowed to release them. They fall on top of each other in a great noisy, squirming heap, sniffing each other's bottoms, biting anything they can sink their sharp little teeth into and weeing on the floor with abandon. It is exactly like all the mothers and toddlers groups I used to take the children to. I feel quite cheered.

"You see," says Mr Young to me afterwards as we carry an exhausted Archie out to the car, "there is a point to you. You have to take care of Archie now. And me," he says as an afterthought.

Back home, Archie wees on the kitchen floor and paddles in it. I happily get the mop and bucket. Oh, it does take me back.

Friday

Harriet's 18th tomorrow. A milestone in her life and mine. I know I usually end with a humorous line (oh, come on, be fair! I do! You know I do!) but this week I want to finish by dedicating this column to mothers everywhere; it really is the hardest job in the world, and most of the time we make it up as we go along and get it wrong more than we get it right, and just when we think we've got the hang of it, our children grow up and leave home and that's it. And we don't even get a gold carriage clock.

But, against all the odds, my own three children have grown up into delightful adults.

And I'd rather have that than a carriage clock any day.

PS Happy Birthday Harriet!