Bittersweet. So "yuri", but no yuri happens, because at 16 year old, you're unsure about everything and the group applies some pressure.
If it goes like I think it will, Aoi probably didn't get invited because she came out at some point and some assholes felt uncomfortable around her, so the organizer decided to exclude her. "What if she makes a move on me? yuck!"
And the MC was probably in love with her at some point too (maybe it was even mutual) but was too unsure to take that step and they graduated without anything happening. Some side characters will be supporting, others will give warnings or be disgusted.
And I see it with an open ending where the two, now adult, women, re-start as friends and maybe more in the future.