"A harem includes three or more characters who potentially show romantic interest in a male protagonist. The sex, gender, or orientation of the harem members is irrelevant as long as they exclusively, or at least primarily, are vying for the affections of the same individual - who may or may not reciprocate towards one, several, or none of these romantic rivals." This is the definition for harem given on this site, at the current point in the story we have one female lead who's certainly interested and one side character who may be romantically interested or may not(personally she seems to be leaning towards the subordinate type of emotional attraction rather than romantic), we've yet to see. I certainly wouldn't call this a harem story.