If you already know when you want to take it, I don't see why you wouldn't register ASAP. Around here there are more popular test locations, which obviously fill up a lot faster than other locations.
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Messages - Blakkout
Personally, I signed up for a Kaplan course. Haven't taken it yet, but my reasoning was pretty much based on how close it was to where I live, and the success of a few of my friends who have taken it.
I pretty much faced the same choice you did, and ultimately decided on taking it this June. You've got extra time for a possibly needed retake, as well as one less thing to focus on the semester you'll be filling out all those apps.
Good luck either way.