Don't rush and send your primary AMCAS application. Take the time to make sure the personal statement is well written and that you have listed all your academic achievements and experiences.  Even if you send your primary application early, you may get your secondary application early.  However, sending your secondary application early does not guarantee that you will interview early.  Admission committees may review your secondary application later in the year because your application isn't deemed high priority.

What is high priority?  High priority are those with stellar GPAs and MCATs.  These people will either get multiple offers because their high numbers plus their personal skills and extracurricular activities make them sought after medical students.  Or these high priority applicants who interview early may not be so stellar in person because they lack interpersonal skills, etc.

The take home message is there is no second chance to edit your application once you send your primary AMCAS application off.  You may hear other applicants around you telling you that you need to send it out on the 1st day possible in June.  Don't get caught up in this time trap.  Take your time and send the primary application off.  Try to send off the primary AMCAS application by August at the latest.