I think there's nothing wrong with setting a date in the future when you're going to stop drinking, as long as you work your plan. Maybe the extra time helps you prepare yourself mentally, and "make peace" with your drinking as you get ready to say your final farewells. Or maybe you take the time to taper off gradually.
Nothing wrong with either of those ideas. If it helps, it helps.
But setting a date a month ahead of time, well, that's a lot of time for your brain to talk itself out of a course of action. Might want to consider moving that up a bit. But on the other hand, you know you.
Good luck
