Responses
The first that comes to mind is "short cake cake." Not sure if this the one you're looking for
cherry blossom after winter?
https://www.mangago.zone/read-manga/l_dk/
https://www.mangago.zone/read-manga/short_cake_cake/
this one is an age-gap but it's still pretty similar to what you seem to be looking for x:
https://www.mangago.zone/read-manga/yumemiru_taiyou/
I remember this manga, set in highschool
I don't really remember the characters appearance, ages or such.
But i remember it being the "shared house" trope. It wasn't an age gap manga, just a regular highschool love manga.
I'm really sorry for being so vague, but it's been a long time since i read it Ó╭╮Ò