Its not like a movie. You don't know.
your girlfriend will turn away or will never go in for a kiss
she'll kiss you on the lips
Well you will know when you want to kiss your girlfriend. As for her, see if she looks at your lips a lot, touches you more, and seems to be getting closer to you. Also a more obvious gesture, is if she leans in with her eyes closed.
Perhaps you can give her a kiss on the cheeks
well depending on how long you have been dating you could just go for a kiss and hope for the best or you could talk to your girlfriend and see how she feels about it.
Justin Bieber has a girlfriend, if he was to kiss another girl he would either be cheating on his girlfriend or kissing said girl on the cheek.
Look her in the eyes, kiss her and then ask her.
I wouldn't let the past get the best of me. I would just concentrate on the now. Your girlfriend is with you and you're with her. Know you guys are a blessing to one another.
Kiss her.
It is normal for some individuals to feel nervous or scared about kissing their girlfriend, especially if it is their first kiss or if they are unsure about how their girlfriend will respond. Communication and setting boundaries can help alleviate fears and create a comfortable environment for both partners.
She'll look at your lips, or move her head closer to yours.
When the moment is right, you will know. She just may be waiting for you to ask.