There are definitely many American seminary girls who would consider it not normal to have a facebook page, but my impression is that there are others who would.
I think it depends on a lot of factors: 1. How many years out of seminary is she? If she is 10 years out of seminary, it is very different than if she is in seminary now.
2. What seminary did she go to? There are a lot of different types of seminaries.
3. What is her background like? She might be very Yeshivish but not from such a Yeshivish background. In that case, you have to look at things differently.
Basically, you really have to look at the individual and not jump to conclusions. You have to see what she is about, where she is coming from and most importantly, the direction that she is going in. It is important to look at the whole picture, and not only the details, especially if you are talking about a grey area. You do want to make sure that she is not addicted to internet and that you have similar views on having internet in your future homes and the way in which you want to bring up your kids, etc.