Should I talk to this girl?

So there is this girl that I know from high school and she also knows me. We are friends on facebook but we have never really talked on there at all. We were polite to each other in school but no real conversation outside of an excursion where we actually got to know each other a little bit better. My problem is that I want to message her and talk to her but I don't know if that is appropriate. Some say it is fine while others say it is creepy. What do you all think?

It should be fine if she's a normal human being and you act nicely. If you want something more from her, you'll notice if she is into you or not with some time, or you can just ask her directly and get it over with quickly. But your post isn't very clear about what you want, so if you are literally just asking if you should talk to her, then yes.