Ashitaba-san Chi no Muko Kurashi - Vol. 2 Ch. 16

[MangaDex]

 

[SotiCoto]

Okay... that opening image clarifies things. If aunt Nukumi was a JK when Hinata was in primary / elementary ... then the age difference between them is less than 10 years... which probably puts her at late 20s to early 30s.

... Younger than me then. Hmm. Despite her lifestyle, she seems more appealing all the time.