There's something I really love about Shimamura's extremely detached, almost third-person perspective; I often found myself thinking like that and I used to think that was normal until someone finally told me that it wasn't. It felt really validating to read how she evaluates everything about herself and how she interacts with other people.
It's also really great how she double- and triple-thinks everything because of this disconnect, because as I learned the hard way myself, the feelings that lie underneath these thoughts didn't go away or become unattached to the thoughts—they were just buried under the words chosen by the brain. So seeing Pancho help her realize the things that she felt, but never identified, was amazing.
I think I agree with the assessment that she's ace, at least with the reveals we've gotten so far. Some asexual people did report that they could still regularly have sex with their significant other(s), as they see it less as a sexual act and more a bonding activity, something that allows them to express love or feel the love their partner tries to express. I can see her doing this with Adachi.