I would definitely add to the chorus - go! The one thing I would say is keep an open mind about other schools in case you don’t get into Berkeley. There are lots of good programs that could prepare you for a rewarding career working with immigrants from Mexico/Latin America. I just wouldn’t want you to give up if one particular school didn’t give you an offer.
I have also studied abroad and know what you mean by the terror beforehand. I had to basically convince myself that I was OK with dying to get myself to go. Obviously, it wasn’t nearly that bad! In fact, I loved it. But I mention this to reassure you that you’re not the only one who found this idea appealing, yet frightening.
I went to Europe on a tour when I was not long out of high school. A bunch of friends were supposed to go but couldn’t for one reason or another so it was me, myself, alone. I had to fly to London and spend a day there on my own before joining the tour. I was skeered, let me tell you (I had travelled alone in Canada but never outside) but I was not going to back down. I had an absolute blast.
The only other time I was really scared was my first trip to NYC. Stories on the news sometimes made it sound riddled with crime. All the fear evaporated once daylight hit (we arrived at night) and we got out walking around.
Now there are few places I’d be afraid to go on my own (like Darfur, Iraq, you know - ones with problems). You’ll realize that there’s nothing at all to be afraid of (well, excepting the normal precautions you take in your own home) and have a wonderful time.
Get your shots, take proper medical precautions, and you’ll be golden.
After reading your recent thread in the Pit, I’m more convinced than ever that you should go. Working with the abused girls in the ophanage could be really helpful for you.