Today is number 12

Well, as I had anticipated for months now, the start of school has set in motion an irreversible process.
My son came home with a calendar from school and he carefully studied it. It was the first time that he began to understood that a calendar was a piece of paper that had a particular function that has an impact on him.  He examined the icons on various dates (a sun for Labour Day, a camera for picture day).

It sunk in.

My son's concept of time is congealing.

Yesterday, after so far referring to yesterday as a few whiles ago, and two days from now being the other tomorrow, my son asked for some confirmation.

"Today is number 12, isn't it?"

Yes, and tomorrow is the 13th.