Welcome to the big 'gamble'!!! I usually book as soon as the window opens. I fly out of Boston, so have flown with Delta/Song into MCO. But, I'm traveling in both Oct and then again in Dec....still haven't booked the Oct flight and don't know what I'm going to do about the Dec one yet. I think I may wait until I see what JetBlue does. Delta/Song usually stays pretty competitive when JB first opens their window. Then, SW will open theirs. It's a huge dilemna for me. I figure I'll go with the best rate, at the earliest time I can...that will be when JetBlue opens...that's when I'll book for Oct and Dec.
Good luck.