To me the fashion thing is almost completely separate from the "loli" term as applied to people.
The "loli" term as applied to people seems, as near as I can figure, to relate even more to body type than to age as such. Although I agree sexualization often/usually has something to do with it.
Basically, a loli is a girl or woman with a physically small and slender, girlish figure who is in some way sexualized, whether through dress or taking a romantic and/or sexual role, active or passive. The appearance must invoke the typical appearance of an underage, even prepubescent, girl, but the person does not have to actually be that young and very often isn't; they are frequently teens, sometimes adults and occasionally very old (vampires and whatnot). That's how the term "loli" is used among manga fans as best I can define it.
The physical appearance is definitely a, even the, primary issue; what that says about manga/anime fans I couldn't say--it is a visual medium, but frankly I do feel that among many dedicated manga/anime fans particularly of shounen material there is a tendency to emphasize, even become connoisseurs of, certain fetishistic elements; it gets a bit artificial for my taste.
So I agree with Inzaratha--Ran isn't a loli. When she's physically young she isn't sexualized. When she's got a romantic/sexual context she doesn't have a loli physique at all. That's why nobody's referred to her as one.
Edited by Purple Library Guy, 18 October 2013 - 06:50 AM.