The only time Use Year has much impact is when you cancel a reservation on short notice near the end of your Use Year. A December Use Year when you forsee yourself traveling in November could be a problem when you cancel. You'll be at the end of your Use Year and when cancelling might be past your banking deadlines.
The December Use Year will be great for December vacations. You'll be starting off your year with the points and if you can't make it still have the rest of the year to make alternate plans.
It's not a major consideration but if you forsee November vacations as the norm for the next 5-10 years it's something to think about. If you think a December vacation works just as well, no problem at all.