Was that not just a confession? That is what happened on page 11/12, right? Like maybe the original japanese makes it more explicit, but in a roundabout way she spelled out that she knew exactly what this looked like, and straight-up says "considering your chances" (our guy has great odds in his favor, obviously) she wouldn't blame him for trying, and then tells him she likes him because she knows she can trust him to be considerate enough to not try something. Then teases him about how he will be less forward now that he knows it is appealing to her. He even admonishes her for phasing it like that.
Maybe I am just coping really hard and reading too much into the limited dialogue and context, but I just don't know how else this makes sense. They are literally discussing how they could be having sex with eachother. There is just no way that with 4 chapters left they aren't mutually aware that they are an item at this point.