Not sure what your age is, but worth heading over to the doctor and ask to have your hormones measured/checked. Hormones give your body a mind of its own which can wreck any "diet". I am not looking for an excuse, I just want to keep no stones unturned, and, your path to fitness straight.
Numerically your weightloss target looks very achievable. Personally I love Christmas because of all the turkey, which is a good , clean protein. Stay off the booze, the baked stuff, and the snacks; eat clean and you should be well on your way! All the best.
P.S. Have a look at a program called "Gracie Bullyproof" which is BOTH a kiddies' self-confidence and exercise program AND gets the adults involved. So you get to exercise WITH your child(ren) and they get to exercise too.