If you are lucky you will get a 2013 book in March or April....
So the correct decision is start now and avoid the rush. By the time you have read the rules several times, marked the changed sections that apply to your vehicle you will be months ahead of the waiting game.
Read the rules, try to not read into the rules, if you have questions ask them in the rules section and expect a variety of interpretations.... the final say is always the SCTA Tech Chair for your vehicle. But not every newbie rule question needs to go there... understanding what you read is half the battle.