I've not even met Her and I get "Jillys" When i want to Call Her

Hi, I have just been introduced to this girl by my friends and i have his Number and Facebook ID and i kinda liked her somehow from first impression. The problem here is we are in different states of the Country so im just suppose to call and make contact and try talking to her but for some reason i get nervous to do this.

Funny, I am an outgoing person if you ask me and im sure if i had met her face-2-face, i wont be getting this nervous. I know all i have to do is call her up and talk to her and it should be easy since she is not even seeing me  but my Question is why do i feel nervous about calling her.

Do i feel an obligation to liking her already or am scared if she doesnt like me, I will be sad?