Well done for going to a dance class, I had a card through the door and thought about going to Legs, Bums and Tums, and that's as far as I got! Oh, then I walked to the bin and put it in 
If you actually want to set yourself a goal for Christmas, and you don't have to, just be realistic, based on how you have done so far and allowing for some potential hiccups, then you won't get disheartened. Have you got to your club10 yet? If that's not too far away, go for that and if you exceed it, then that'll be even better. If this is your first Christmas on SW then you might just want to lose as much as you can by then without putting an actual figure to it, and be prepared to put as little as possible on over the holiday. The first year I didn't put any on (how, I have no idea) the second year I thought I was doing the same but put on 6!! One of the best things that the consultant did was make us guess how many syns in all the various chocolates, that's enough to put you off!