Half a liter is ⅔ of a standard bottle of wine. Even if it is only 11% ABV, this still equates to 55 ml of ethanol. An average 14 year old male weighs 112 lbs, about 70% of an adult’s size.

So if we extrapolate linearly, 55 ml of ethanol would be equivalent to 78 ml of ethanol for an adult, which is 6.5 shots, assuming a 1 oz shot

Yeah, but the wine was supposedly watered down for the children too. And that would be the maximum limit too.

Everything you're saying is true, but the wine was watered down. I grew up in (Eastern) Europe and I used to have a glass of wine with my parents at dinner time when I reached my teens pretty much every time they did (we had a small vineyard, like most people, and wine was plentiful). However, I was mixing it with mineral water (50-50) and with a heavy meal, I never got drunk from that.