She is sitting in the library, studying. It's her most common pastime, by hours; spending time with her sister is more enjoyable but Jaromira prefers to socialize more broadly and Katarzyna would only get in the way. This is better on net; the two of them share a room, so it isn't as though her sister's time is entirely hogged by the other girls who call this boarding school "home." Or at least "prison." Katarzyna doesn't mind it, though; the school library is excellent, and basic manners and care for the books has endeared her to the librarian to a sufficient degree to lubricate the interlibrary loans process when there's something she wants to read that they don't have.
"Still! Even if my powers fail to be sufficiently metamagical that doesn't mean no one will manage it, and I still have high hopes."
"Maybe we'll find out why magical girls are a thing in the first place! Although I've heard some people think they existed before the historical record suggests and that they just died of it for some environmental reason as soon as they starscaped and it folded in with all the child mortality."
"Huh, fascinating thought--what environmental reason, though--Isabella I think you might have accidentally nerdsniped me."
"Oh no! I don't think it's credible that there's an environmental reason that would have stopped being a factor everywhere on the planet in the same month."
"I suppose, but that introduces strictly more complexity than magical girls being a thing at all."
"Anything fun in school or does it all pale in comparison to crackpot origin of magic theories?"