Personally I think it's lame. Even though you want to do it in a c/f way, you should just go for a kiss, whether it's your birthday or not. Why don't you run a kiss test on her instead?
Lay down your ground work, then whenever you're ready to perform the kiss test make eye contact and hold it. Quickly glance down at her lips than back up at her eyes and continue holding. Then lean in somehow. Either over to her ear to whisper something to her, reach in and grab her hair as if you're pulling something out, whatever. Just move in and see how she reacts. If she seems comfortable, then you can go in for the kiss without worrying about if she wants to or not.
Ofcourse you should be reading her all night to know where her interest level is and you should have a pretty good idea on how she'll react to the kiss test.
But I personally think asking for it just for the sake of getting a kiss is lame.
Cgraz