Original Commentary

Sofia, at least according to the cast page, is 18. I do not think it has been stated forthright what the legal age for drinking is in YISF (ND has stated it's 21) but you can be sure it's not 18. Although it seems that no one really cares about it as strictly as they do in real life. -Isabel

Modern Commentary
Sofia isn't old enough to drink at a bar. But they're not going to a bar, are they? - Terrence