Sooo, everyone is okay with a 20 year old stalking a 16 year old because "shE iS nOt LiKe ...

Nope, people have already called it:
https://www.mangago.zone/home/mangatopic/19603353/

It's 4 years gap and he isn't do any sort of exual stuff with her? Then I don't really mind. 300 years ago it was normal that 16 y.o. were getting married. Even in Romeo and Juliet ( Juliet is 14 when her mum is telling her she was married two years already and have her child being Juliet age)

At that age, a 4 year gap is considered huge nowadays, because at that age each single year involves huge development, like a 'Windows 11' dating a 'Windows Xp', and things yet more muddled if only one of them is a minor... That's why nowadays it is usually recommmended that minors don't date someone 4 years older without their parents' being aware and giving permision. Moreover: 20 year olds, while not that much older, are legal adults (so they have access to stuff that minors can't) even though they may not be mature enough to realize important things as they go, at least enough to avoid ending up acting in an abusive way to 4-year-younger partner (yeah... even though they're ñegal adults, in my experience too many 20-year-olds can, and do, end up being at least emotionally abusive/manipulative to younger partners, because of their own sheer immaturity...).

That's why, though this is a historical fantasy setting and though I'm much more invested in her revenge aganst her family (so not really that interested in paying that much attention to the ML and the romance), the truth is... yeah, that scene when they met in the kitchen was a bit icky, watching him being a bit way too touchy feely, like touching her hair over and over and stuff, like some perv... (didn't think age even mattered right then, bc dude was doing it without any permission; that's GROPING). Hopefully it won't be so icky from now on, but if the author insists on making this ML keep acting like some croping perv, I might drop this, no matter how much I want to know if she gets revenge on her mother..

Hmm, I am old, age gap between me and my husband is 3 years. I had always calling him "young" one because before I met him I wanted someone at least 5 - 6 years older than me. Probably even now I wouldn't go for someone my age and reason isn't technology gap ( that also exists in my generation) but mental and emotional development. Male are maturing slower than female when it comes to these two things, and to be honest in relationship those two are the most important. Of course I can be mistaken and this generation ( teenagers now don't care about mental and emotional development as much as they care for technology knowledge and skills) also there is of course difference between someone under age and adult one, that is why he should not start any s.ual things with her, especially that he doesn't know that she is reincarnated. This time of age marriage or any kind of relationship in early 20 or teenage years isn't required ( it's time to have fun) but even 50 years ago that wasn't issue ( not to mention settings of this manhua)

That is just disgusting.

Yeah it wasn't an issue 50 years ago, but 50 years ago "adolescence" didn't last till people were 30-ish while the legal threshold still stayed firmly stuck at 18... A contradiction that nowadays allows us to have 20 year-olds who are A LOT more immature than the 20-year-olds of previous generations. Nowadays even though we have 20-year-olds who are legally adults, enough for them to be legally able to move freely, watch porn freely, to all the have sexual and 'financial' freedom they want, drive anywhere and buy alcohol for themselves as much as they want, they're still 20-year-olds who're more often than not still not mature enough to have solid judgement of situations enough to avoid certain social risks and peer pressure, let alone to avoid involving any underage friend or partner of theirs in things that they absolutely shouldn't be involved.