MC, even though everyone hates you, I still like you! You're like a dumb puppy! Adorable but stupid.
PS: Don't think Miss Flirt is meant to be the FL. She might be first person to get a redemption arc though.
Echoing the comments that say it's too slow. I think it's just too slow because the MC isn't really doing anything related to the plot yet. We're just kind of following him though his day to day life.
If the MC had some personal problem he focused on fixing while leaving this "development" of the study group in the background, I think the pacing would fix itself. For example, where the f**k are their parents? In this situation, I would think it would be the parents that put the most pressure on them to fix their grades. I feel like I would have been 100% disowned if I repeated a year. Or at least sent to the doctor to search for some disability.
Alright, that's the problem. The author isn't threatening their living situations at all with this "repeat the year" thing. They're just doing whatever they want with no consequences and no hints as to why there are no consequences.