Happy Hustle High(2003)

H3 School!

What happens when an all-girls' high school reigning tomboy finds out her school is about to be filled with boys!?

Hanabi Oozora is a rambunctious 16-year-old tomboy who comes to the rescue of her less assertive friends--sometimes in exchange for food. So what does she do when, all of a sudden, her all-girls' school is about to be integrated with an all-boys' school?!

She meets and falls in love--naturally--with one of the three most popular and handsome boys in the Student Council, Yasuaki Garaku! Unfortunately, Yasuaki doesn't care for girls...and when the girls' Student Council clashes head-on with the boys' Student Council, Hanabi steps in to become a member--hoping she'll change Yasuaki's mind!

(Source: VIZ Media)