Sugar Soldier

From Chibi Manga: From the time she was a child, Makoto was always compared to her beautiful sister. So she decided to become just as awesome as her sister for her entrance in High school. But it didn't really work... One day, she met a guy who's popular and older than her. Suddenly, Makoto can't make her heart stop beating so fast?! So now, she can't stop thinking about her school life!