Christmas is one of those days when you can ease off the diet.
One thing I've noticed in the past is that if I bolus for the carbs in a shop bought mince pie, I'll go hypo. I halved the carbs given on the pack and it worked for me. However, I've recently been diagnosed with coeliac disease, so things could change drastically this year.
Enjoy your first Christmas as a diabetic. Don't get too wound up about your low carb diet, just celebrate and enjoy yourself. Remember to test, before and 2 hours after eating, looking out for highs and lows.
A very early Happy Christmas to you!