It was my daughter’s fourth birthday last week, and it didn’t really feel especially momentous. She has, after all, been claiming to be four for about nine months now. Like all preschoolers, her self-image largely revolves around her age, and height, and any number of similar benchmarks that she tabulates obsessively.

She has been known to cook the numbers; referring to her nursery as “school”; engaging tiptoes, for deceptive purposes, when being marked against height charts; and always, always, always, wilfully misrepresenting the fractions involved in her age. Before she settled on “nearly four” as her permanent age, she’d decided she was “three and three-quarters”. I don’t want to quibble with the mathematical nous of a small child, not least one whose academic instruction is largely my responsibility, but this was only about a week after her third birthday. Undeterred by our corrections to the contrary, she simply raised this number sequentially, according to an internal clock of her own conception. Three and five-quarters … six-quarters … seven.

Her passion to be bigger and older stops just short of wanting to be an adult, however, and any suggestion – no matter how playful – that she is as old as, say, her parents, evokes disgust. When I turned 40 last year, her eyes went wide as saucers, in the manner of someone encountering a traveller from plague times.

“You’re nearly 40 yourself,” I said, deploying that inerrant wit which has made me a world-famous literary humorist. “I’m NOT!” she said, genuinely wounded, and in a tone that implied my saying this was tantamount to suggesting she only had months left to live.

If her finally turning four was, thus, anticlimactic for the rest of us, she gave no indication that this was true for her. On the day itself, she clambered into bed at around 6am, filled with excitement and slapping us awake with her small squishy fists. We traipsed downstairs to show her the presents we’d stocked there the night before, which she attacked with mercenary glee.

Sometimes I’ve heard other parents say things like “We spent all this money on this present they begged us for and then all they want to do is play with the box.” I don’t have those kinds of children. Mine yearn for large, expensive heaps of plastic that emit as much sound and light as possible.

My daughter tore through the wrapping on the largest present first – a Paw Patrol boat she had mentioned to us, oh, seven thousand times – and shrieked with capitalistic delight. Then came some books, a stamp-making kit and some cards, all discarded quickly so she could lift the two biggest items and bring them into the sittingroom to play with by herself. These were the aforementioned boat, and a karaoke microphone gifted by her aunt. (This features a light-up base designed to engender epilepsy in human beings, and transmits a child’s voice at ear-splitting volume, making it the sort of present you’d be forgiven for presuming you would only give a child if their parents had recently maimed your dog.)

My name is Séamas O’Reilly – or at least I thought it was until recentlyOpens in new window ]

For her party, we crammed into a soft play centre down the road, a site for several of our birthdays of the past few years. An hour’s tumbling through a four-storey padded cage made the dozen or so kids present pleasantly exhausted, and they decamped, euphorically red-faced and sweating, to a barren little function room for chips, nuggets, cake and games. There, the ambient heat had been calibrated by someone inspired by the reactor excavation scenes in Chernobyl, but we were too busy enjoying the chance to sit and chat with amiable parents to notice very much.

It was only once we got home, and toasted her birthday with three of my siblings, and six of her cousins, that the day began to take its toll. Perhaps it was the adrenaline crash from all that cake and fried food. Maybe it was the sight of other children playing with her freshly minted new possessions. Whatever the cause, she lashed out around 3pm, screamed that this was the “worst birthday ever” and demanded she go to bed. Since it was her party, we agreed that she could indeed cry if she wanted to, and so we dutifully carted her upstairs.

Séamas O'Reilly: She has been known to cook the numbers; referring to her nursery as 'school'. Photograph: Steve Ryan/ The Irish TimesSéamas O’Reilly: She has been known to cook the numbers; referring to her nursery as ‘school’. Photograph: Steve Ryan/ The Irish Times

To our amazement, she fell asleep, only to bound back down an hour later like a new woman. She apologised for the outburst, gamely shared toys with her cousins, and even ate some non-fried food with a smile on her face. “This,” she said, between dutiful bites of cucumber, “is the best birthday ever.”

We couldn’t help thinking that her younger self would never have made such a gracious and dignified recovery. Such tact, class, and remarkable personal growth. But she’s older, and wiser, now. She is, after all, three and four-quarters old.