Edgy girl will come back to rescue Hina.
She went back to college to become a "proper adult" and once she gets a job she will come back.
That is my head cannon.
If lucky science babies in the future.
Yes that is my cannon too
Seems like that was what the author was going for. Just before she left she tries to actually take a sip of the wine and realizes, much like a kid, she hates the taste. She then cleans up the bottle, leaves it by the window, and draws the curtains so the light shines on both it and her letter. I'd interpret that as her returning as the adult Hina looks up to, the one who would pompously sip wine I guess.
