Different cultures count differently. eg Jesus was not born in zero AD but in one AD. His whole first year of life he was considered to be in his first year.
I think some countries count age this way too (hopefully someone can confirm to satisfy my nerdy curiosity).
Powderhorn@beehaw.org 1 week ago
I’m actually in the same boat. I’m three months out from being here a decade, but as with infants, we start rounding at a certain point.