Each person has their own Castaway Club number. The number follows
you. If you book a cruise on your own, you will still have your own, personal, Castaway Club number. And that number will show what level you are in the Castaway Club.
Castaway Club level really doesn't have to do with who books a cruise. Only the person actually taking the cruises gets the cruise credits, not the person booking the cruise.
On the
DCL website, you can create your own account (that's for bookings, has nothing to do with your Castaway Club level).