Read clear, non-verbal signs from your girl.
A few signals that show her readiness can save you from making the wrong move:
She stares at your lips a lot.
She starts talking about kissing, or kiss-related topics. Is she talking about how she has never had a great kiss? is she revealing to you that she appreciates a great kisser? If so it’s time to pucker up and grace her with your kiss. She pauses, as if expecting a kiss, especially at the end of the date. Be sure that there is no other reason for her apparent pausing and expectant state.
If she is not appearing uncomfortable and appears to like the intimacy with you, then it is assumed that you can go in for a kiss.