Alright. So we know some of the nations' human ages.
But not all them, and Canada's has never been confirmed.
I'm going to look at what seems to cause aging, and argue that in modern day, Canada is 19, making him and America twins.
Okay, first of all, let's look at Canada's history. APH Canada appeared to have been born out of French settlements, and the first French settlement was in 1604, though Canada was claimed for France as early as 1534. This would technically make him older than America, whose would have been born in 1607.
However, that's not how growth and aging appears to work in Hetalia. America canonically grew up first (to a teen, because I don't think he was an actual adult when he revolted), which was explicitly tied to his economy. Canada followed not too long after, however, so this doesn't make America older, either.
Looking at some of the other characters, two things seem to influence aging: economy (and by extension, political and economic influence) and independence.
So, it would make sense if Canada were a bit younger than America, right? Because while Canada's not a third world country, they're still not as economically or politically influential as America is--
Belarus and Lithuania: *are also 19*
Oh.
Lithuania can be chalked up to the Polish-Lithuanian Commonwealth, with his time under Russian rule and less-than-great economy afterwards stunting him from aging further.
As for Belarus...
Belarus has a terrible economy, so she doesn't really have a political or economic presence.
As for independence, she has been independent for about 34 years of her life, total.
Canada has a clear edge over her in both areas, so it makes literally no sense for him to be younger than Belarus.
So, if Belarus is 19, so is Canada.
So yes, Canada is 19, making him and America twins.
