Chicchai Senpai ga Kawai Sugiru

An ordinary run-of-the-mill guy named Takase starts working in the Sales Department of a certain Real Estate agency, and his senpai at this job, Komai, looks more like a middle school girl than an actual adult due to her height and incredible cuteness! As they grow closer together, how will they deal with this unusual situation?

(Source: MangaUpdates)