When to Book Flights on SW for December out of BUF?

[shaycamp21]

We usually do a summer trip but will be doing a short trip to WDW (Thurs -Sun) at the beginning of December. I have never flown at this time of year so I have no idea when would be the best time to book. Prices now are ok going down to MCO $108 (though not non stop which I would prefer since we will be travelling with an infant) but coming home they are quite a bit higher. Is is better to wait or book now. Thoughts?