Ah, don't think of it like that. It wasn't money wasted. She might just like you, like you and have the same concerns you have -- your mutual friends, jumping into something, so on.
She could think you don't want to jump into something...you said she knows you are a virgin, well, maybe she's respecting that. Maybe all guys have simply just wanted a fuck and with you she can simply have fun and see where you both go. If she went up at the offer of drinks, she might feel like she was saying 'let's fuck' and so on.....
So much you don't know. Don't jump to conclusions. Don't over think it. Maybe text her? You said she was a text girl. Aren't you two going out Saturday? If so, text her tomorrow to see if she wants to go somewhere before hand. Hasn't she made all the moves so far? She might be over thinking this as much as you -- for instance, if two days ago, she said she was going to sleep around, she might have gotten home and thought about how you might have taken that, like she was slut or something. She might have over thought her end, so....all I'm saying is calm down. LOL.
If she's hanging out with other people, well, okay, but don't jump to a conclusion that she's brushing you off.
Did you have fun?
Did she have fun?
Do you want to see her again, or do you simply want to have sex?
Could she want more than sex from you, and therefore is slowing down?
Lots to think about, I guess! I hope I helped out, but really, it's all up to you and what you think/feel.