Facebook adding friend help?

[oneandonlyme!]

So theres this girl i go to school with, and she has a facebook and so do i. I thought hers was like really private but then my friend said u could find it on the search thing. that didnt work but it said someone commented on her photo so i clicked that and like it took me to the page where it says she only shares certain info with the public blah blah blah. But where it usually says add as friend, its just blank. And on peoples friend lists where it says add as friend by people u arent friends with, it doesnt say anything by her. How do i add her as a friend??
Oh and i know her email but it doesnt come up when you search that either and idk if she'll add me cuz shes kinda weird bout stuff like that