My personal feedback on this is: her being so accustomed to a modern time in a short amount of time is genuinely impossible.
And it seems to me that the only reason why they only like mc is because she knows how to fight and beat up the bullies. But they don't know that the person that they're talking to isn't actually her.
Honestly you’re so right it’s so strange of the author to do that and I totally forgot she was someone from ancient times thank you for pointing this out, but I don’t know it might be the real park dajin feelings so that’s probably why she’s feeling like that because even tho it’s her mind it’s still park dajin heart and body so idk book just confusing me now lol

I don't want to feel like that person but it just feels like the main character has a savior complex.
A Mary Sue complex also
Also do I find it kind of weird that a grown woman is possessing a dead girl's body but she's falling in love with an underage boy....
And her having to have feelings for the Male lead, genuinely makes it a bit conflicting: but to me the the mc isn't doing it for the girl that she's possessing I think she's actually falling in love with the guy herself.
'The villain' just has attachment issues... And she's not really a threat because she's not really being portrayed as one despite the story saying that she is.
Secondly the plot feels so familiar to another webtoon that's basically about a woman who gets stuck inside of some soap opera....
Secondly everything just seems so easy and fast paste. And it's not even leading anywhere....