My son turned one last week. The day marked the end of what has been both the longest and shortest year of my life. From the instant he was born, it’s felt as if my son has always been part of this family. I don’t mean that in an obnoxious, heart-eyed, this-was-always-meant-to-be way. I simply mean that I haven’t slept for a year and I don’t really know how time works any more. Whole years have passed in some of the afternoons I’ve spent with him lately. Entire galaxies have been born and thrived and withered and died in the time it’s taken him to eat a mouthful of bloody porridge.

How the hell is he one already? First he was born, then I blinked, and now in his place is a little boy who can walk and has teeth and knows how to switch off the television at precisely the most important moment of anything I ever try to watch. It’s not exactly the most unprecedented development in all of human history – child gradually gets older – but it’s the first time I’ve seen it close up. It’s honestly quite hard to grasp. A year ago, he was a sleepy ball of scrunched-up flesh, but is now determinedly his own person. I can see everyone in him – me, my wife, my parents – yet he’s already separate from all of us. He’s giddy and silly. He’s a show-off, albeit one who’s irrationally terrified of my dad. He loves running up to people and waiting for them to twang his lips like a ruler on a table. When he gets tired and barks gibberish in the middle of the room, he throws his entire body into it, like he’s trying to shove the noise up a hill.

He’s leaving milestone after milestone in his wake and tiny parts of me along with them

With every tiny development – every new step he takes, every new tooth and sound and reaction that comes along to ambush us – we’re confronted with a slightly different child. Photos of him taken in the summer seem like dispatches from a million years ago. Photos of him taken last week seem like a different boy. He’s blasting ahead as fast as he can. He’s leaving milestone after milestone in his wake and tiny parts of me along with them.

He’ll never again be the tiny baby who nestled in the crook of my arm, sucking on my little finger in the middle of the night while his mum slept. Nor will he be the baby amazed by the taste and texture of solid food. Soon enough, he’ll stop being the baby who totters over and rests his head on my shoulder whenever he gets tired, or who laughs uncontrollably whenever I say the word “teeth” for reasons I don’t think I’ll ever work out.

But I’ve had a year of this and it’s OK. He’s never going to stop changing, and I don’t want him to. This sadness, this constant sense of loss, of time slipping just beyond your grasp, is an important part of this process. He won’t realise this, of course. He’s got years of unbroken progress ahead of him, where everything will always be new and he’ll keep obliviously brushing away all the silly old farts who tell him how much he’s grown.

One day it’ll creep up on him. Years of his life will pass in a moment and he won’t be able to understand where they’ve gone.

But it’s OK. You can’t hoard time. You just have to make the most of what you have. Happy birthday, kid.

@stuheritage