A good rule of thumb: If you have her phone number, you can be her Facebook friend.
Here’s a cool little app that rearranges any text string into various funny anagrams. If she seems to have missed the trick, you can challenge her over chat to solve the puzzle hidden in your post.
I think until you’re in a relationship, you should just keep it, press the like button, don’t put anything too scandalous or flirty out there.
But it’s really about, you can only control what you do. So I think you should be more concerned about what people are posting on your wall, that the people you’re dating can see.
Click on the audience selector of your new status message, choose “custom” and then make it invisible to everyone but her.
She’d get a huge shock to see your declaration of love out there for the world to see, but trust me – she will feel a tiny bit proud of you for being so honest about your feelings (don’t forget to go crazy ;)).