Only I am 17 years old

Childhood friends Kota and Mei were third-year students in high school when Kota suddenly died. Seven years later, Mei returns to her hometown and visits a place with mid-winter cherry blossom trees that were special to her and Kota. To her surprise, Kota, who is supposed to be dead, appears. He is still 17 in mind and body while she is now 24. Kota can only be here while the cherry blossom blooms. Will he be able to tell Mei his feelings with the time he has left?