Maybe, but we don’t have a date for that, do we? Still, it wasn’t His incarnation or His birth that saved us from sin, although they were necessary parts of the plan. It was His death on the cross that paid the price. So, if I had the power to change the calendar (and I’m not Anti Christ, I won’t even try) I would start the calendar on the day of the crucifixion!
Nine months before Christmas the Church celebrates the Annunciation. March 25. My point is that it should be a bigger celebration because it affirms our pro-life beliefs (God did not enter the world on Christmas, He entered it in Mary’s womb nine months earlier).
And it is the moment God intervened. Yes, the Crucifixion and the Resurrection are what make salvation possible. But once God entered the world, that was all a fait accompli. God would not fail.