It'll work for some girls (a select few), who will think it's sweet.....
but for the most part, there are much better ways .....
you don't want to ask her for permission..... because you are a man and you are in control. You might as well sign off a contract giving her your balls.
Two methods I would recommend:
the first is David D's kiss test. You play with her hair, then touch the tip of her hair with your fingers. At the same time, look into her eyes, then slowly down to her lips, then back up to her eyes. If she isn't ready to be kissed, you'll be able to tell by her reaction just to that.
the second is a fun one from this forum (wher I read it anyway, not sure where it originates from)
you ask her "do you like surprises?"
if she says yes, kiss her. If she says no, kiss her and then say "sorry I forgot you don't like surprises"