Kay is incredibly adorable and I can't be the only one who's shocked that she's only dated Katsu. This certainly isn't a criticism, but I imagine that the guys in CO would not have left her alone.
I gotta wonder where in CO is an all girls' school... I went to private schools, but none of them were boys/girls only. edit: ok, so I looked it up and some do come up, but it still feels like non-coed schools are now rare there.