Sim card problems with iPhone 5?

I'm getting a second hand iPhone 5 from a friend. I heard that the Sim card for the iPhone 5 is smaller than regular ones. My friend is taking the Sim card that he originally had in the phone. I'm l have a plan with Vodafone and would really like to keep it so what can I do? I'm going to need a new Sim card aren't I? Will Vodafone transfer my plan over to a new Sim?

In the UK all you have to do is go into a Vodafone store, they will transfer your a/c on the nano sim the IP5 uses, your number and contract stay the same

Sim card all have a 19 digit Sim card Number SCN, the one you are using is deactivated and the replacement nano sim SCN is activated on your a/c

10 minutes tops longer if you have to Q