Kinoshita Brothers Don't Stop!

Mayo Kinoshita has three extremely good-looking older brothers, each with his own unique personality. The oldest is a working adult who's a bit of an idiot. The middle brother is a hard-core otaku. And the youngest is a narcissistic high school boy. Because of her older brothers, Mayo is distrustful of good-looking guys in general, saying that "handsome guys don't know how hard life is." But then she meets Eo, a fresh-faced good-natured boy in her class, when they are assigned to work together for the school festival....

(Source: Hana to Yume, translated)

Notes:
- The chapter count includes 2 extra chapters.
- Originally a one-shot that won the Hana to Yume Draft Cup to earn a one-volume serialization run, which was further extended to two volumes.