She pegged Chiaki as Hana's lover in her first appearence too so it's possible she just knew about Hana's preferences all along, maybe even told by Hana herself since Hana never got defensive or surprised about the assumption.
"She pegged Chiaka", interesting, interesting. Jokes aside though, yeah sometimes that parent intuition is really strong. There's parents that aren't aware their kid is gay, but there's also parents that know their kid is gay before the kid even really knows haha