"Mum, give me three words that describe me," one of you said to me last night, as you twirled around the sitting room, fifteen minutes after you first said goodnight.

"Enthusiastic, enthusiastic, and enthusiastic," I said, and you laughed.

"Okay give me three that don't describe me."

"World famous singer. Now go to bed."

There are so many other words I could choose to describe you and your siblings, but right now, as September sucks the life out of me, yet you continue to twirl, enthusiastic sums it up in one handy word.

I'm in awe watching how excited the three of you get about things that don't seem all that important to the rest of us - the perfect French plait, using the ketchup first, walking on your hands.

I envy your enthusiasm for making jam, making forts, and making cards. Your unadulterated love for pancakes. Your endless energy for climbing up trees and jumping on beds.

Your unbridled passion for this week's favourite TV show, and for regaling every scene of every episode. Your predictable enthusiasm for an entirely different TV show next week - current passion quickly quenched.

Your love of water slides, with no concern for water temperature. Your love of rollercoasters, with no concern for speed. Or height. Or the near-death-experiences that worry your least brave parent.

Your always-on attitude and devotion to trying something new. Or something everyday - like picking blackberries and picking nail varnish and picking up sticks.

The dancing around the room while you talk, the never sitting still, the endless, unselfconscious energy.

Where does it go, when does it end? When precisely is the crossover from enthusiasm to jaded heap on the floor?

Somewhere around the time job meets bills meets responsibilities, I guess, with a generous sprinkling of age. The passage of time, the wearying of bones. When it's not possible to walk on your hands anymore, and it doesn't matter who gets the ketchup first, and making forts seems like it leads to a lot of tidying up.

So may you be little as long as you can. May your joy for new things prevail. May your enthusiasm flame blaze high - if I could bottle it, I would. But I can't. So instead I'll write it here, and when the inevitable wane begins, we'll know how it once was.