That makes sense.
Or it might be their official band name in the future. Even tho Jian Yi their band's going to be "One Day" maybe they'll change it into "19 Days" or something
Since Jian yi disappears for high school it makes sense that they reunite at 19 though
Oh! And they Jian Yi did mention he returned when everyone's already in college but he still has to finish high school
Yeah
19 days... Their days of when they're 19-year-olds? But middle schoolers aren't 19? They reunite when they reach 19? If they do end up separating like how it's implied in the earliest chapters