I agree to the romantic setting. First of all, how long have you been together? I'm hoping more than a month has gone by lol.. How old are you? And her? These are all questions that need to be thought about before you try to put the moves on her.
Maybe you and her should talk about if she thinks she's ready. I mean, don't tell her your planning on finding that out later, but ask her how she feels about it. You will be able to see it in her eyes if she's scared or happy. Drop the subject after discussed briefly, and continue to make her laugh and be her friend. Continue to make her feel comfortable with you.
You'll know when the time is right. And she will too. If she's not ready, she'll let you know. And once again, if/when she says she's not ready, please remain her friend, her companion. If you start to act different around her if/when she says "no", chances are she won't be saying "yes" anytime soon. Good luck :)
P.S.- Be gentle with her ;)