@Kami_Nana i think we're in the same "ara ara young boy loves elder woman tropes" boat, cuz i think i've read some explanation the same way you said it in https://mangadex.org/title/32726/sensei-wa-koi-o-oshierarenai or maybe we're not cuz that line was pretty famous from a novel author (i guess???), they even made an anime with that subject called tsuki ga kirei. although if you're might be intrested for more "forbidden love (cuz of age diffrence)" then you should read it lol
Seems like some of you don't know. She basically confessed to him at the end of the chapter.
"The moon is beautiful, isn't it?"
https://www.tsuki.world/world/the-moon-is-beautiful-isnt-it