Interesting - it seems that Aria has some sort of memory problems. IIRC that was already hinted at earlier with her apparently not remembering Khara at all, but this chapter seems to help support that idea, considering the implication that she and Ichika's grandma used to be close.
Speaking of which, Aria's (possible) memory problems make me wonder just how close she and Ichika's grandma used to be. Before it seemed that Ichika was her first kiss, indicating that Aria went further with Ichika than anyone else, but now it's a bit unclear...
Of course, I could just be reading too much into this.