I'm going to USA for a whole year as an exchange student!

I’m going to live with a host family, but I know nothing yet.

What can I expect, what can I not expect?
Any personal experiences you would like to share?

I’m 17 (in like 9 days) so I will be attending regular high school. I have no idea where in the US I’m going yet nor when I’m traveling (I’ll travel in August though).