Hey,
Well I came to the UK from Australia not knowing anybody, and went straight into my job and BA. I've not had the same problem as ChewyTheWookie. I've found everybody, especially a lot of the older women and definately the older men to be absoloutely lovely, and I'm only 21. (Only had a problem with one lady CSD on my 6th flight)
In my almost 2 years at BA, I've made a great bunch of friends at the airline too, who I see regularly outside of work. As I didn't know anybody else in the UK, all my friends are from the airline. I won't say it was easy...you have to put in the effort and call people first and suggest you swap numbers etc, but it does happen if you want it to.
I suggest that you try and move in with a few crew members who are in the same situation as you, and then you'll make friends with them and meet their friends etc etc. That's how it happened for me.
Good luck and go for it, it's the BEST fun!!!!