@alyssa, the song means whatever you make it mean.
But the meaning to me is that the person in the song's mouth is frozen, she cannot speak, she is turning to ice. Maybe she is asking a guy out, maybe it's something as simple as talking to them, regardless the girl feels like she can't speak because she see's the guy as having an ego and blowing her off. All she needs is a little emotion, but even when she gets the courage to get down and say what she wanted to, the person still blew her off. (Gave her the "cold shoulder"). Even though she built up the courage to say whatever she was going too she still wishes them the best "it's a little late but you know I just want you to be happy".
I think you get the just of what I mean.