That looks to be too old for her to be in high school. It's probably Kouji using a similar design.
W-Well, see.... that kinda thing happens with the mobs, yeah?What's this? This chapter's background characters are all kinda oddly dressed, no?Regrettable mobs.Cutting it fine this time too, eh?Yeah... sorry 'bout that... and every time...Deadline dayOh no, as long as it's in on time, there's no problem!