My Study Buddy's Secret Life

So, I'm this college student, mid-twenties, and I've been hitting my stride pretty well. I keep to myself mostly but have this one study buddy in my calculus class, let’s call her Mia, just because it sounds boring as hell and we both know we're not really friends. We’ve always kept our conversations about homework and the occasional joke, all super tame stuff. So here's the thing that happened recently. The semester started off like any other, but then Mia invited me to study at her place. I mean, there’s a coffee shop nearby, right? But okay, whatever, maybe she had some sort of weird motive in mind. Long story short, we get into this study session and things start getting... weird. She starts talking about these elaborate fantasies she has, you know the usual: dungeons, masks, all that jazz. I was like 'uh, cool?' but also kind of intrigued because Mia always came off as so serious. Anyway, she pulls out some stuff from her nightstand drawer that made me raise an eyebrow, leather cuffs and a blindfold, anyone? I tried to act casual about it but inside my head, a hurricane was happening. She suggests we take a break from the books and just... you know. I'm not one for experimenting like this, especially not with someone so seemingly vanilla. We ended up giving each other these weird role-play scenarios that night, she's got some wild side under all those textbooks, turns out. And let me tell you, it wasn't exactly what I expected. It was kind of hot and also kind of awkward because it felt like this whole setup was just a fantasy for her to indulge in with whoever would take the bait. I left early but couldn't shake off that night for weeks afterward. Is there something wrong with me? Am I the asshole for not wanting to go full-throttle into whatever this was? She hasn’t brought it up again, and honestly, I'm kind of glad about that. We've since stuck to our normal study sessions and she’s back to being the 'serious' Mia I thought I knew.