Baka ni Kokuhaku

Story

Ayumu Otsuki is a space lover with an ambitious dream—to meet an alien. Lacking friends or romantic experience, she starts an Astronomy Club by herself, to create a place where she feels she belongs. One day after school, she was putting up a poster to advertise the club when an upperclassman stepped in to help. The upperclassman introduces herself as Hayami, and Ayumu immediately falls in love at first sight with her! Ayumu's mind is now consumed by romance, and she goes all out to share her feelings. However, Senpai seems to already have other interests. She fell for a fitness junkie?!

Synopsis via AniList (English).