I had a couple of friendly conversations with this girl I like, should I add her on facebook and how she feel?

[Valerie]

We had a few more conversations together as we were lab partners in groups of 4. And im sure she likes me. We flirted a lot together, and she has given me chances to ask her out but i never did. I smiled at her once and she had a huge smile on her face during bio class.
So should i add her on fb?
I would ask her out if i would see her again. I just finished the semester and i have no idea if she will be in my class next semester.
And the reason im not adding her so soon is cuz I dont wanna seem creepy nor desperate. Girls dont like that. And I wanna know how girls feel when their guys they like add them on fb

[Tony]

just ask her out

[Sandy]

are you really pondering this? really? are you kidding? your asking me if you should add her on FB? grow a pair, buddy.

[Shahriar]

well, you can do something clever. Such as send her a request and send a msg-hey, i saw you when searching for a frnd of mine! Would you mind to be my frnd!?? Obviously that'll not make you creepy...