You can certainly drink yourself into coma with beer. Teens drinking 6-10 beers is not an uncommon thing at parties at that age.

That said practically the 16/18 distinction also isn't that important. If you are 16, you typically hang out also with some people that are >= 18, and which will then buy the other things. People might not necessarily start drinking with hard liquor, but the time to it is typically not 2 years.

Source: I'm german, and had been 16 and 18 a long time ago.