I'm not sure deadlines serve much of a purpose honestly. It will just cause you to countdown to New Years and as that deadline approaches it will have an effect on the way you act. A change that may or may not have an effect on her. See where that leads? You could actually be delaying her path and progress to something that may be beneficial because you want it too much.
So, I think it might be much better to say at New Years you are going to revisit how you feel and consider your options at that point.
You also have no clue how going through the holidays will make you feel, or how it will make her feel. Let things happen as they will and don't try to force them.
Absolutely live for you just don't assume you can do that only one way. You can be happy alone just as you can be happy alone and in limbo while still M'ed. Not much would change other than financial aspects and maybe the ability to date(not like were ready to anyway). That pain is not going to disappear if you do D, its just a piece a paper remember. So don't go thinking having the D final will change much. The only thing that might happen is you letting go(psst, you can do that now, its just hard).
Patience.
Accept what is, let go of what was, and have faith in what will be
