Why place her in a box until you know her better.
You may elude to being "just friends" and she could turn out to be the love of your life.
Go out with no expectations or assumptions, just have fun and be you. When you know her better then you can either escalate and date her, make it clear your not an exclusive dater, or make it clear you are only interested in being friends. Thats not a step you are at yet.
You can bust her balls i nthe email, make a crack at her for not having a facebook profile...tell her she should set one up its soo much better then plain email...right?
Im sure you'll do fine just dont over think it, have a fun time, show her the real you...and go from there.