@Shizomist Depending on the author's age, "kid" could refer to anyone from the age of 10 to the age of 110. It's not really an age bracket, it's a term of endearment.
Also, while I would definitely never encourage anyone to break their respective country's drinking laws, whatever they may be, let's not hide behind our pinkies here, underage drinking has always been a thing. As well as, like this chapter shows, people legally drinking whose maturity hasn't quite caught up to their age.
Wine goes into the blood stream faster than beer, also you need to watch out for size. Wine glasses are fucking enormous. So yeah I can understand it at least a bit.