No time like the present!

At least if you get into P1 a bit before T-Day it might help keep you more focused and your off plan treats on that day to a more manageable minimum and then just back into after that. The holidays and holiday parties are there every year. It's often more about settling for a draw or minimizing losses than it is about winning each and every battle. Don't necessarily strive for perfection, but at least if you get into the swing of it now, you'll probably still be a whole lot better off than if you wait until January! It's more about making consistently good choices and even if your choices are for small amounts of off plan foods, at least they are conscious choices in the larger context of an overall direction and plan and not just mindless eating for the sake of eating whatever you want with the prospect of getting back into at some point in the future, which may or may not actually ever come about despite your current best intentions.