We are heading to CN in April for our first trip and are signed up for Romance Rewards. We may want to try the trading places so we can see CSA. My question is: can we do this on our first trip? It says that rewards begin with 3-13 nights and I'm not sure if this means that we can do this after spending our first 3 nights there or on our next trip after a 3-13 night stay.

Also, if we can do it, any recommendations of how many days in advance we need to sign up? Thanks!