Ikemen Oneesan wa Sou Yuu Me de Miraretai

Saku-nee (Saku Housaka), a first-year university student, and Shio (Shion Yoshiba), a first-year high school student, are childhood friends. Saku-nee is a handsome princely-type girl, and for Shio she's someone he looks up to. While she treasures the relationship they have, at the same time she also harbors the desire: "I want Shio to see me as a woman!!"

(Source: Natalie, translated)