We met last week through mutual friends, ended up hooking up for a hot and steamy night. Went a couple days later on a follow-up meet and she was noticeably more distant, colder, stiffer, being in general very resistant. I stopped things there, got up and left, although she said she still wanted to meet again, to which I vaguely said OK.

She ends up texting me that she wants to "end things" as she's "too young for me" (I'm 18, she's 17) and that she had fun. I didn't say anything and fast forward a day later, she texts me "are you mad at me".

I've been confronted before with this kind of situation but I handled it like a complete chump then, and would like some advice on how to deal with it proper. Any help appreciated.