I was an exchange student in hugh school and in university, and really, those are two completely different experiences and I recommend both.
In high school, I really got to take a dive and soak up all of the culture, family life and so on. I lived with a family, had siblings and parents, so to say. I went to school and was pretty worry-free, to be honest. it was amazing. And hard. And exhausting. And rewarding.
In university, I was on my own. I had an appartment I shared with some other students, but it wasn't all that easy getting to know "locals". A lot of exchange students end up hanging around with each other (I also observed this in my own University back home).
going to Canada on an exchange in 1995 caused me to become German in 2011.
I met my now-husband there.
...we're going to never let our daughter talk with any foreigners, ever ;-)