Senior and Her

Tsuzuki Rika is a first-year high school student. She is in love with third-year high school student Minohara Keigo. Meanwhile, Keigo Minohara is secretly in love with Okita Aoi. She attended the same high school and is now a first-year university student.
(Source: AsianWiki)
~~ Adapted from the manga series "Senpai to Kanojo" (先輩と彼女) by Atsuko Nanba.