<p>If you have enough time to make sure your essays are strong, and you already have your teacher recommendations it is almost always preferable to apply early. If you retake the ACT and do better, you will be given the opportunity to submit it if you are deferred. </p>
<p>The only case where applying early would not be preferable is if you have to rush the application to get it in by the deadline, and it is obvious to the admission committee that you rushed it.</p>