I would say... Go to her b-day, surround with her girlfriends and leave impression on them... She will notice that you hang with them and that can make her curious. So you cant loose here.
Or she will come to you and her friends (or b/c of you, or b/c of her friends and its a great chance to start conv)... Or she can ask her friends what were you talking about with them, are you cool etc... Thats why you should leave good impression on her gfs

. And yes dont expect 2 much... Its all about her that night!

. Play it cool, you are not impressed by her but you think shes nice/ok

... That should work

. GL HF !