Unless you never notice and remember that this 2 character already appear before and one is one of the roommate, that is really a big jump of assumption, many story have side couple.
and i doubt we never see the 2 lead girl again, it doesn't seem like they journey is complete
But the younger one (sorry, names are hard enough even when they're in my native language group...) has that sense of ageless maturity about her, even then...