Your 17-year-old Days

Lee Jae-Gun is an ordinary high school student in most respects, except he's always had a crush on his childhood friend's brother. He thought everything was going well, until one day, a new student with the same name as his crush, Lee Jae-Ha, transfers to his class and begins to interfere in their relationship...!

(Source: KakaoPage, translated)

Note: Chapter count includes a prologue.