Hi all, I just had this on my mind, and was wondering if anyone would be willing to offer their perspective on the situation. I've been seeing this girl for a little over a month and a half, she's 19 and I'm 22. Things have been going great, we share commonalities in almost every category you can think of. However, the last 2 weeks she's been busy with school and HW (which to be fair, finals are coming up and she's very dedicated to her classes) whenever I've asked her out for dinner or a date, but she's made time to ask me for rides to and fro (I have a car and she doesn't). Normally after these rides we'll hang briefly for an hour, kiss and cuddle a little, but that'll be it. We used to be going out to eat, spending the night together, sex life was great, hasn't been the same these past two weeks. Basically, in fear things were fizzling out and I was starting to just be used for rides, I asked her if something was up and if things had changed at all between us. She said she wasn't looking for anything too serious (which I was somewhat aware of going into it, and although it's not my preference I'm okay with it), but what caught me off guard is when I'd ask her about it she was literally on the verge of tears/slightly crying when she'd say she liked me but didn't want to commit to anything serious. I'm just confused what would've caused her to express these emotions if she's not even wanting a serious relationship? She has a lot more relationship experience than me and has even told me in the past "no guy has ever treated me like you have" and how she's "obsessed with the fact (I'm) in (her) life". In all transparency, after we talked we just moved onto another Convo and listened to some music, kissed and cuddled and I was on my way. But it's still been lingering in my mind why she'd act that way (as in crying) if she just wants to stay casual with me? The only reason I asked her to begin with and still have this on my mind is because of how much I like her to begin with. Also, I have very limited relationship experience so if I'm overreacting please let me know.

TLDR: when asking a girl whether she wanted to be serious or just casual, why did she start crying while explaining she didn't want anything super serious?