The timing of your first stay may depend on when the building you bought into is ready for occupancy. For exmple, if your buiding will not be ready for guests until November 15, 2005, then you cannot use your points for a stay (at any of the DVC resorts) that begins prior to that date. The date that applies to you should be in your paperwork or you can consult your guide.
Since you bought directly from Disney you should be able to make reservations immediately (subject to the usual booking windows and your building ready date). Sometimes the system doesn't have your account/information until after closing, but if that impacts reservation making, it's DVC's problem, not yours. If you have a problem getting MS to make your reservation, you may need to get your guide to help.
Best wishes-