It all depends... If she already has the thoughts about wanting you for a BF. Then it'll work. If she doesn't have those ideas you might wake them up in her mind for doing this. But that's not a safe move. If I were you I would try to work her up atleast a little. You already know eachother, so you have knowledge about her you can use, eg. what kind of styles she likes when listening to music, watching movies and so on...
Try to set a mood. Invite her to your place and start the evening with something normal, like a buddy filmnight. But as the night proceeds, use the kinos like moving closer to her and then when the film reaches some point where some form of romance is displayed use it to your advantage. But don't overdo it! This is important, you can't start throwing yourself over her. It takes a little time to leave the LJBF. But once you've started you'll get there.
The rose is a great idea, but don't expect her to throw herself in your arms for it. She might even give you a bad responce, don't get hung up on that if it happens! It might be because she is surprised. Once she start thinking about it and telling her friends about it she'll have small thoughts about the sweetness in your action.
Remember that it is the small things together with the big picture that gives you the great future
Hope all goes well! And post us about your progress
/R.O