I’ve experienced both situations.
I did my first two years of university in my hometown in the States at a school many of my friends went to. Towards the end of those two years, we were all still friends, but we had grown apart, met other people, and weren’t nearly as close as we were in high school. We were taking different classes, working towards different degrees. It’s not like high school where you’re all assigned to the same class – chances are good you’ll all be interested in different things, and you’ll begin to gravitate towards the people in your classes because you’ll automatically have things in common, like what assignment is due next week, what were the notes for the lecture you missed, which essay are you doing, etc.
Anyway, I then moved abroad and have spent the past three years finishing my degree here in Scotland. I wasn’t completely alone, as I moved here to be with my (now) husband, but he works abroad 6 months of the year. As far as university goes, obviously I knew no one to begin with. I’m not an overly social person but I still managed to make friends and find people to talk to in class (mostly other foreign students). I even made one really good friend who was my bridesmaid when I got married last year. We get together frequently. And now that I’m graduating, I find that this friend of mine is the only reason I’d want to stay in this city. As much as I don’t want our friendship to end (and I hope it will somehow continue), I can’t stay indefinitely in a city I otherwise dislike.
Assuming you’ll be living on campus if you go to the first school (I’m not) you will have a much easier time of meeting people and making friends. A lot of people there will be in your situation and will be eager to meet people and make friends. And e-mail and online chatting are great ways of staying in touch with the people back home.
My take on it is that high school is over now. Don’t hold on to your past so tightly that it prevents you from going where you want to go. There is a whole world out there which extends far beyond your current experience. You and your friends will all have Internet access and e-mail accounts at whichever universities you attend; you will not be completely cut off from them. There will also be plenty of opportunity to visit home – TG, Xmas, spring break, summer vacation, etc. And if you do go to that first school and you hate it, you can always transfer back home. (Try to give it a year though, so you have time to settle in.)
Good luck in your decision, and cheer up! College is infinitely better than high school. You make your own schedule (think: all afternoon classes :)), take the courses which you find most interesting, choose the activities and events you attend, and get treated like a responsible, intelligent adult. It’ll be a fantastic experience. Enjoy it, and try to make the most of it!