This is a fine anime but don't get your hopes up just because of the rave reviews and high average score.
Story: 5
It is a nice idea but poorly implemented. The MC is supposedly a college student who is reincarnated into a 6yr olds body. Put simply the actions and mental capacity shown by her is maybe that of an 8yr old at best. While she does have her prior knowledge she seems to lack any kind of rational thinking, self-restraint, emotional maturity or any other adult qualities. When compared to a series like Youjo Senki (The Saga of Tanya the Evil) in which a salaryman is put into the body of a little girl. There is a clear difference in that that Yanya clearly still think and act like an adult rather than a child with a little extra knowledge.
I think where this can most be seen is in her utter lack of planning, while there is a long term goal of making books. Most of her decision making is reactionary i.e. the wood got burnt so I'll try a different material or I'm ill so I'll rest, but she never really bothers to look into her illness even when she finds out that its the devouring and that it is treatable. She does not so much as inquire as to what the treatment is.
As it is a world with magic it could be exactly the same show but instead of being reincarnated, Mian touched a magic amulet (at a mysterious travelling traders stall or similar) and gained another person's (the current MC's) experience and knowledge causing a slight shift in her personality. What this would achieve is essentially the same thing by giving her the extra knowledge, change in personality and the obsession with books but explain her still acting and thinking like a child. Furthermore, as only nobles have magic, for the most part, it would provide a good reason not only why the amulet was assumed to be normal but what made her able to interact with it. While it is not a perfect or original story opener is would hold more water than "I just happened to die and wake up in a different body".
Art: 7
The art is rather basic and is nothing special, that being said I do like the diversity of buildings shown. From the poorer areas to the merchants, while the shots are reused they do still give the desired effect. While the building in themselves are nothing special (hence the 7) in quite a few animes it seems the buildings are generic stone and are almost all identical to the point where every building in every town could be copy-pasted.
Sound: 6
The sound again is just fine and nothing more, not that I was expecting anything special.
Characters: 2
The character all seem very one dimensional and there is minimal if any character development. The only character, other than the MC, who gets any expansion is Lutz. This seems to just be a way to make up for the lack of personality of Main herself. There were several points in each episode where I found myself thinking "there is no way that Main is an adult" (or college student), as I went into above (see Story) she seems to think and act like a child, which for me at breaks my suspension of belief and means I can't get invested in her character.
Enjoyment/Overall: 5
This anime is OK the characters are underdeveloped and the story progresses enough as to not get overly stale but was it not for the quarantine at the moment I doubt I would have finished it.