What's the latest I can take the MCAT this year and still apply at the earliest possible time?

My GPA kinda sucks so I'm trying to apply as early as possible to give myself the biggest advantage I can. Right now my MCAT is scheduled for April 28th because applications are sent to medical schools late May. Is this the right move or can I delay it even more (I feel a bit behind on studying). Thanks!!
Source: Student Doctor Network - Category: Universities & Medical Training Authors: Tags: Pre-Medical (MD) Source Type: forums