No reason not to, but unless it is a really good deal I personally would wait. Feb is the slow season at DC (and SeaWorld, etc). In the past, you could get really good deals on DC directly starting around Sept/Oct, and especially on Black Friday week.
My DC day coming up in May was $202 w/ +3 park add-on including tax on Black Friday. Same ticket now is $539 before tax. A few years ago the Black Friday deal wasn't as good, but all days were priced at the cheapest price, so still a reasonable savings at that time.
If you buy direct from DC, it is fully refundable. UT charges at least the 5% restocking fee - that'd be quite a lot for 13 tickets. So IF I were going to buy now, it would be direct. But honestly I wouldn't, they've been pretty consistent w/ good Fall deals.