I was on an online dating site for about a year where I met my husband, but rarely I got anyone asking to meet in person. There was one guy who emailed me and asked me to go out with him on the second email, but I felt really uncomfortable. For me I was much more inclined to talk for a few weeks or even months before meeting, but I guess it depends. I think usually people wait a few weeks and throw back and forth a few emails before meeting. If you're uncomfortable with it, tell her that you'd like more time to talk before meeting in person. If you aren't, go for it.