Is my friend acting weird, or am I just getting annoyed easily?

If you 2 are moving apart soon, maybe she is starting to notice all the differences between you and her and subconsciously she's playing them up so neither of you are too hurt when you move away from each other. Or maybe she is having delusions of grandeur for the future and trying to get out of this little town you both are in and she's trying to distance herself from the "small town" mentality of the people around her. Who really knows? You should talk to her and have a frank conversation with her about it all, say some examples that you mentioned above and tell her it's bothering you and you want to know what's going on and just see what she says.