Taiyou yori mo Mabushii Hoshi

Sae Iwata, a slightly tougher-than-average girl, falls for the gentle smile of Kouki Kamishiro, a delicate boy, back in elementary school. By the time they enter junior high school, Kuoki has grown into a charming and popular teen who now feels out of reach. When they are assigned to the sports festival committee together, Sae’s long-hidden first love begins to stir once more.
(Source: Amazon Prime Video, edited)