Afterschool Minkowski

One day, Ako Roki, a girl who dreamt of a happy high school life, touched a tangerine at a shrine and suddenly jumped four years into the future! That meant Ako lost out on the chance for a normal high school life with her friends, and she became depressed and down on herself. However, what awaited her at her new high school were more unexpected incidents involving "time" and "oranges". Set in the city of Imabari in Ehime Prefecture, three high school girls scramble about in this bittersweet coming-of-age SF story!

(Source: Comic Days, translated)