1 free month of gold question

So I'm about to connect online and get Xbox Live. Now my question is do I have a choice of when to begin my free trial, or it does it automatically after I create the account?

Reason is FIFA 10 comes out next Tuesday so I don't want to waste this 1 week now... but I do want to get on Silver atleast to add friends.

It's when you sign up.

When signing up it will ask if you want to buy gold, say no and it will offer you a free month.

^ yep. Sign up for a silver and it will ask you if you want to pay for a gold subscription and say no and it'll give you a free month.