I think this series is fine overall, but has some glaring problems that makes my eyes roll every other time.
For starters the whole maturity and romance displayed by 5~7 y/o kids simple makes me uncomfortable, it would be much more plausible if they were just 4~5 years older, as they were just becoming teenagers and have their feelings blooming and what not. Main is an exception since she was an "adult" before, but the whole lack of common sense and getting flustered by a 5~6 boy and what not makes me doubt.
The whole devouring plot line was overdue and went way too long before it was explained and solved, by episode 5~6 I was wondering how the heck she didn't die in such a dire medical/living conditions when she seemed to collapse every other day, then they took other 5 episodes to tell the main character about it and she didn't even bother to ask about it seriously, she only found out it was mana in the last episode. For such a book loving person, she should've read some fantasy histories and she didn't even tried to test it she could use magic? Clearly it's possible due to the crushing in the last episode.
So these plot holes makes me wrap my head, but otherwise it's a fine series.