I don't have much advice for the sunny disposition, except maybe try to recreate parts of your life from back then? Go hang out with some of the same friends, do some of the samme hobbies. Just try to pretend the ego-blows never happened.
Alternatively, do a google search on baby penguins. Trust me on this.
As for losing a friend... You just need to show her that you're cool, and that there's no awkwardness. Humans tend to follow cues, and if you're acting cool and normal, she'll probably follow.
Pretty basic, I know, but sometimes humans really are simple
Haha, that's great news! Go Dvil!
I'd say the "other country" part sucks, but... you're going to another country. And I'm not envious. Not one bit. Nope.
To me, it just sounds like she doesn't put much stock in this. Can't say I blame her. She casually knew a guy some time ago, he writes her back in a friendly manner, and there's no harm in responding.
FB is extremely low-pressure, after all.
You don't say how explicitly you asked her out date-wise, but I suspect that as far as she's concerned, you're just trying to expand your social circle or something. You aren't even that persistent about it (you have long periods of silence, too).
I dunno if it would help to be more explicit, or more persistent. Maybe she is trying to tell you something. But IMO it's more likely that she just has so much more going on that one perifery friend doesn't really register.
I'd push her out of my mind, stick to friendly FB likes and comments until July, and if she doesn't contact you, try one last time. Maybe even with an explicit date invitation.