I met this girl during vacation and we spent 3 weeks together. She was also on vacation and she left to go back home (a city a few hours away) and I'm leaving today (out of country). I'm starting Uni in a few months and I know I won't be able to see her until next year.

I told her I liked her about 2 or 3 days ago on text when she began to ask me questions about my crush and all the answers started matching her description. She told me the feeling was mutual, and I was over the moon. However, we never officially asked each other out, so perhaps it would be presumptuous to title us bf and gf, but she grew up conservatively with the only knowledge of romance being from exaggerated romance movies, so she has assumed we're bf and gf. Immediately after telling me she liked me, she started talking about marriage in the future and didn't seem to understand that I wasn't trying to make a lifetime commitment so early until I explained it to her.

I thought I could be patient for a long distance relationship to work, until I realized I couldn't and that we were incompatible in many major ways. She's a social butterfly, I'm very asocial. She's religious, I'm not. We've grown up very differently and I don't think our lifestyles would complement. I sent her a breakup text (if you wanna call it that, even though we weren't bf and gf), and now I'm wondering what I could've done better so that she doesn't feel hurt by the whole thing. I mean, I'm her first experience with romance and I'm already leaving her after like 2 or 3 days. She hasn't seen the texts at the time of writing this. I realize this is my fault, so feel free to verbally abuse me as long as something useful is suggested too.

If it's relevant, I've had one short relationship before this around 2 years ago. She hasn't had any. I'll update when she sees the texts.

Edit: forgot the TLDR; I'm a girl's first experience with romance and I basically broke up with her after like 3 days because I realized we weren't compatible despite being the one confessing first. What could I have done better so that she doesn't feel hurt by the whole thing?

Edit 2: Update. She replied. All she said was "ok". No more, no less. I don't know if she took it well or took it horribly, but there's officially no going back. I'll post an update on my profile if she says anything more, but otherwise, case closed. Thanks for the comments, all.