Go for it! It's a once in a lifetime experience and I'm sure you'll enjoy yourself. I studied for 3 years in the UK and it was the best time of my life. If I could do it all again I think I would have done a year in America too, but the UK was great.
On the other hand, you have to go.. so if you're not sure don't just do it because we think you should.
I'm sure you'll miss your family, but you have to spread your wings at some time and I'm sure they'll visit and they're only a phonecall away. If you really are homesick then you come back, no harm done. But it's better if you try then always think what if...

Tash