I really hope you can make it here, even if we never get to meet (but wouldn't it be cool if we did?). For fear if sounding like a broken record, America really is a wonderful country full of amazing people. You'd have a blast here and you'd probably get a lot out of it, especially if you wind up at a good school.
Don't worry, I'm the same about Poland (I took literal break from writing, to not spam) ;). As of good school, I think that most of the ones I have on my list are really good. As of fitting in, that's a completely different thing. To say that I don't particularly excel in social interactions is among the understatements of the century. List of people I get along with and could call friends for one reason or another boils down to my room mate, two guys that I roleplay with (fun fact: I might turn out to be a GM of a guy who might end up being a TA for one of my classes. Talk about conflict of interest :D) and a post-doc from Netherlands with whom I have one of those amazing dynamics (both in research and in 2 vs 2 table tennis :P) that can be best described as "a whole that is greater than the sum of its parts". Most of the people along with I study don't seem to enjoy my company. This is going to sound terrible of me, but the main hope it'll change comes from the fact that I have started mathematics along 120 people and to second year qualified only 34 of them, and ratio on physics looks even grimmer. Although it's a bit shit that the main reason some people might talk to me is a rapid choice density reduction. Sorry if it seems like I'm a downer here, not really what I want to convey here. It's, like most things that I write, as honest and precise set of statements of facts that I can make. I'm actually quite chill about it ;).
Pfft. You'll probably be fine here. Like I said, if you do anything socially awkward, you can just play the foreign card. "Oh? You eat tacos with your hands? That's weird. In Poland we use a spoon and an apple peeler." If you're a math major, you'll probably find some nerdy friends that you'll get along fine with. Any trouble there, go to a local gaming shop and see if they have an list of gamers looking for a group. That's a good way to make friends too. Just be cool and you'll probably be fine. :)