They did Violet Evergarden, the age gap there is not stated directly there but Violet is around 14yo at the time the anime starts and her love interest is around 15 years older
Dude, just read some of the author's other work lmao
https://mangadex.org/title/784614ea-949f-43ed-952f-9881677aa477/dog-and-my-family-circumstance
This is just her personal fantasy of owning a cute petboy with the added bonus of him bringing in some spice into her boring life, the girl being...
There's some spellings mistakes in the chapter, in page 10 in the top right panel it says "ncident" instead of "incident", on page 60 in the middle panel it says "ther" instead of "there"
There's a mistake in page 9, in the middle panel MC says "was she really a student A from our school", also, in page 23 Kuro says she has to curse five generations, it should say seven
I think that might be part of the point, Hikari, despite knowing MC for longer never saw him for who he was, just as a little brother, MC did the same seeing her just as a challenge to conquer, in this chapter Yami saw the real him and that's what got to him
Hikari used to talk about her childhood friend as "Ta-kun", Yami only knew him as Yuu so she didn't connected the dots until ch11 when one of their friends made a pun on his name in the group chat, it's even possible He and Yami were still dating at that point and she decided to break up with...