The 12 on a clock is a compromise to match between a 1-indexing oral culture and natural 0-indexing use case (which came from the Sumerians who had a better number system).
I don’t know the history of reported ages of Western babies.
> quite irritating really
Yes that is my point.
There is. We call it 12 for some crazy reason (it goes 12 AM, 1 AM, 2 AM, ..., 11 AM, 12 PM, 1 PM, ...).
> no zero year in our calendar
Which is quite irritating really. New Year's Day 2000 wasn't the start of the 3rd millenium, because there was no year zero.
> East Asian babies are born with age one year
But not western babies.