If your financial situation and personal life allow, do the online basics. The wait for academy basics may be indefinite. Nothing you learn in basics really matters. It is a summary of the what, when, where, why, and how of ATC and aviation. A small percentage of the info from basics is usable for the Enroute/Terminal portion of the academy . . . . maybe 10% and ALL OF THIS WILL BE REVIEWED. If you want to improve your chances of succeeding at the academy, TAKE ONLINE BASICS NOW, and spend the time between finishing and going to OKC learning the map (mainly for Enroute but may apply to Terminal as well). LEARN THE MAP! The map is the first thing you get graded on and there is no reason to not walk away with 2/2 points. Doesn't mean a whole lot if you ace your evals, but it is a good confidence boost and a few points for many is the decider between success and failure.
EDIT: Forgot to mention knowing the map like the back of your hand is arguably one of the most important things for success at the academy. I am sure people get away with subpar map knowledge but your chances of success are much higher if you do know the map well.
where can I find this map.........................