I know its early in my pregnancy because I'm only 21 weeks but would like to know how far along I have to be in order for my obgyn to schedule my c-section so that I am better prepared

It can depend on the reason for the c-section. Will this be a repeat surgery? Is there a specific reason you are having a c-section? Usually they try to be within a week or so of your due date, but again, it can depend.