Responses
I think she is 26, cause she did not go to uni, she probably married very soon after highschool, had Koto-chan and just matured fast because of it. But she does act very much her age sometimes, that's how I see it. There's probably not a big age difference between her and Yuki.
I can't believe she's only 26 and they all acting like she's lived an entire life just cause she's divorced w/ a kid. I know full undergrads her age, like cmon.... Maybe it's a mistranslation and she's actually 36 or something but that changes very little