Yeah, it's great and all but as everyone has noticed, the tags (including MangaUpdates "age gap" category-tag) all point to this building up to the... obvious, and rather questionable, romance.
...Well, she's not an actual kid, being roughly thirty pre-isekai-ing and all, so I'm not going to stop and wait to read it out of the mere possibility it goes in a weird direction.
(I mean, almost all reincarnation-y isekai have weird age-gap problems if thought about too hard—I'm undecided as to whether this would be any worse than the usual, on that front, or just more obvious. But the main problem here would be the now-established adoptive relationship.)
In the meantime, though, it's nice fun fluff, while not especially original but no worse than usual for the genre, etc.