Grooming is a pretty serious term. If i remember correctly, noona is 3 years older than the rest of the group. The story started in jiwoos last year of highschool making him 18 and noona 21. I think its safe to assume that maybe 2 years have passed since the start of the story making ji woo 20 and noona 23, and they only started dating recently.
Yes age gaps this small can be considered weird when they're this young compared to if they were older like 31 and 34. And we can also acknowledge that an age difference of 3-4 years like a junior/senior with a freshman is also strange .
But i think this situation has more nuance and saying that noona groomed him is a stretch.
I do find how their relationship came to be a little sudden though. We could tell jiwoo had a crush on her early on, but i still cant tell where their relationship came from on her end lol. It felt like the author was just like "oh yeah".
I feel attacked ... My boyfriend and I have 4 years age difference. He's 19 when we meet and I'm turning 23 that time. But oh well before we entered the relationship I told him about this things, what people might thought about our relationship. But he still pursue me (▰˘◡˘▰)
You should research the word grooming before using it.
Yall dont get me, I dont like their romance ONLY with jiwoo and noona. Especially, noona knew jiwoo when he was a teenager lmfao. It felt so weird. Tho I love kayden and gestella lol.