Slow Start

Following an unfortunately timed case of the mumps, middle school student Hana Ichinose ends up missing all of her high school exams. Unable to stay in her hometown, Hana moves into her cousin's apartment building and spends a gap year as a "middle school rōnin", before finally attending high school a year later than planned. The series follows Hana as she spends time with her new friends, Eiko, Kamuri, and Tamate, without letting on that she is a year older than them.

(Source: Wikipedia)