A 28 year old that looks 30 playing a 25 year old that cries

For the most part I liked this movie. Just the idea of living among so many people of different nationalities in loving relationships seems like a fantasy that one would wish to last forever. However, the first thing that bothered me about this movie is when Xavier was crying on the plane just because he is flying south of the French border to spend a year, not abroad, but next door.

Why would a 25 year old played by a 28 year old that looks like a 30 year old be so upset about just going for a year of graduate study just across the border? He's not even an undergraduate. He should be somewhat seasoned and eager to see the world by then. When I was 20 I went to study in Spain and flew from the US. I was ecstatic to escape, elated standing outside the doors of the Barajas airport in Madrid and waiting for the bus and in pure bliss weeks later to have made so many wonderful friends from so many wonderful places. I didn't want to go back home. I had to, to finish University.