I read this months ago, iirc, the chapter 0 is the future, and the story teller is the MC, each chapters we can see how they both interact with one another, then we go to the present like back in forth. this is quite interesting cause there are too many possibilities, the present time where they all adult fortold that they weren't together, but there something much more, I think.
anyway, I'm just saying there are possibilities of a plot twist.
the title is translated:If I Can Encounter Koshiba Aoi today.
so the possibility of them meeting again is not guarantee but we might know why is that? or how it lead to this.
anyway, I hope it has happy ending.