Hmm. I've dated girls before without knowing them really. Kind of a learn-as-you-go thing lol.
But it could be a sex thing. If she's a girl, might be more natural/safer for her to get to know a guy first. So friends first.
But I've also been incredibly patient before too. And gotten to know/watch people before making a move. That's characteristic of ESTp to really size someone up first, and judge them.
Overall it sounds like she's interested. Especially if she mentioned she has to know someone first, and liked you originally and held your hand. I'd say go for it.
How do you go for it?
Well, if you're INFp, you're probably really shy. But just put yourself out there for her to contact you. Can you message/chat with her on facebook? Text or something? If she's SLE and interested, she'll want to start talking with you more/hanging out with you/spending more time with you. Could be a fairy-tale friend-first thing that grows.
Not to forget, if it is duality, the beginning stages are really tough. Getting to know each other. Most likely to fail early on. So just be patient.
Keep spending time with each other.
And of course, I love Mountain Dew too.