Roderic said: this is blatantly a pun on the fact that nobue is sixteen in the original japanese books and animu, and was published in america etc as twenty.
the romanji... no clue
Actually, she was always 16 in the manga, but in the anime, they bumped up her age to twenty. Can't have a high schooler smoking and getting drunk in the afternoon.
For shit sake, it's practically the starting joke of episode one of the anime.
You've been smoking that whole time too....no, actually, you guys are the ones who really haven't changed!Ah, Onee-chan, look at this!I'm home~
...what are you guys up to?Onee-chan, you haven't changed much in the past 4 years, have you?
Except you don't wear your school uniform anymore.