There's a funny error in the description of this manga:
"The 16-year old Nagisa is her sister's stepson, suddenly sent to live with Ai when his parents left for an overseas job. Wary like cats, these two loners 10 years apart in age will have to make a new life together."
On literally the written line of the first panel of the first page, it says that it is Ai's 30th birthday. That means that they are 14 years apart, not 10 years apart!
That's a good catch. Then again, it's not quite as bad as Funimation's description of the Otherside Picnic anime saying that Sorawo and Toriko are high school students, not college students.
It's good that the story is addressing the taboo nature of a potential relationship between Ai and Nagisa, as well as how Ai, as the adult, would take the brunt of the backlash if their relationship came to light. Most age gap romances that I know of have the younger person take the initiative to confess first, but the idea that confessing could cause problems for Ai will strongly discourage Nagisa from saying anything about his feelings.
It's nice to see the story proceed at a slow burn, but I hope they don't drag things out for too long. I'd like to see Nagisa confess within the next few chapters.