@smithy
It may be 2004, but birds that perform on the first date still get a rep and it's not good to be a slut. She didn't have to text you afterwards, but she did. She said that she'd like to go out again. She didn't have to do that. "As friends", well, I can see how you could interpret this as a fob, but the "let's just be friends" usually happens later when it means forget about it. Right now maybe she doesn't want to be seen as easy.
(Then again, she might just want to get close to a friend of yours. You never can tell how devious chicks can get, but if that were the case she'd probably be coming on a little stronger then stringing you along).
Basically it seems like an open invite and you're not overly invested emotionally at this point so if you like her and you wanna see what happens, just go along with the flow.