Being a 4-page manga, pacing is indeed an issue in this story, but I think that sometimes it is justified to just skip and give incomplete answers to the readers since the answers themselves are trivial. We know at the beginning of the chapter that they did not have a full conversation, because if they did, we’d get to see it. The author is simply skipping the boring parts and leaving it for flashbacks and assumptions which, given the format, is ok imo.
You can't seriously say that these answers are trivial.
The story is ignoring all the tension and conflict that had been building up for several chapters. Whatever conversation happened after Mitsuki asked the question would not only contain the answer to the question but also continuations to many other things: the fact that Mitsuki is a girl, the fact she pretended to be a guy, her reasons for doing so, the distance they kept from each other for a bit, why they care, etc. All of this was built up and none of it is resolved, addressed or developed simply by having us assume Aya said "yes".
Besides, even if we could make assumptions that answer all of these questions, why not show it? You came up with your own headcanon about what happened so even if we assume you're 100% right about the events, wouldn't you still want to see them? We've just been denied a major culmination of this story.
Imagine if in The Lion King, the story went from Simba looking uphill to see the wildebeest stampeding toward him to Simba having already left and we only learn through dialogue that Mufasa died and Scar took over.
This is what just happened in this story.