When I was a student, we did a student exchange with France and England. In 8th grade we hosted a guy from Rugby in England (the town is famous for it's school) for 2 weeks and I later went to Rugby and was hosted by his family. In 10th grade I went to Evreux in France and was hosted by a funny big family (grand parents, parents and 4 children) for 3 weeks, later he stayed with us for 3 weeks.
All I can say is that these trips where some of the highlights of my school time, it was great fun to stay (and party
) in a different country with a different culture, and when I had to travel home I had always wished we could stay there longer.
Imho these trips are the best way to learn a language, as you're forced to speak the language and the people surrounding you speak the language aswell.
So, I can just second what the others said: Do it!