The manga you're referring to, Shounen ga Otona ni Natta Natsu
He moved to the hallway, his heart racing. He opened the door, expecting a delivery or a neighbor. Instead, standing on his porch, framed by the fading twilight, was a woman wearing dark sunglasses and a wide-brimmed hat. shounen ga otona capitulo 1 mangadex
Inspired by this premise, here is an original story following a similar theme of transition and unexpected encounters: The Summer of the Blue Comet The manga you're referring to, Shounen ga Otona
One humid Tuesday, his best friend, Hiro, burst into his room with a "revolutionary" discovery."Kenji, stop playing 16-bit RPGs for one second. Look at this." Inspired by this premise, here is an original
Ryuuki is the classic "focused" protagonist—he has no interest in girls and dedicates everything to his craft. However, Chapter 1 quickly shatters this status quo. The Catalyst: An Unexpected Encounter
Kenji lived for the "thwack" of a baseball hitting his glove and the quiet of the suburban summers. With his older brother away at university and his parents constantly working in the city, the house was a hollow shell of echoed memories. His only company was a collection of old retro games and the flickering glow of late-night variety shows.