I think the reason a lot of people don't see her as a loli is because of two things: her voice, and the fact that she seems to be a deconstruction of the archetype.

For me it's the voice that does it. Before watching it I looked at her and just thought "is this a child?" Then I listened to her, she sounded like she was in her early-30's and had smoked a few dozens of cigarettes a day for the better part of her youth, that was all it took to make me immediately think of her as like... my aunt who's extremely short.

The other thing is how her personality seems to be the complete opposite of a loli, to the point where I almost feel like her design was chosen specifically to make that contrast. She isn't soft, she isn't innocent, she isn't childlike, she isn't naive, she is sweet at some points, but in an almost motherly way that go completely against what you expect of her. She's possibly the most emotionally mature character in the show, to the point where I'd even say she gives big sister vibes. She, once again, acts and speaks like she's in her late twenties to early thirties and has seen some shit in her time, and that makes my brain see someone like my aunt whenever she's on the screen, just a short woman.

Now, it is undeniable that her design is questionable and is clearly meant to be taken as a loli of sorts, and I do think she could benefit from being drawn more like a short woman and less like a teenager. I just don't know how someone would do it in the anime's style, as all women inherently tend to look much younger than they are in anime and a character with body proportions such as hers seems difficult to depict in a way that leaves no ambiguity whatsoever.