Jews did not celebrate birthdays. Pagans did. On only 2 (maybe 3) birthdays in Bible, someone died. Pharoah’s, Herod’s, and perhaps Job’s first children.
Early Christians did not celebrate Jesus birth for first one or two hundred years, and even condemned the practice when pagans wanted to introduce it.
We are specifically instructed, on the other hand, to celebrate not His birth - but His death - often. The dates of His birth or death are not important. What occured in his death is all-important. Our salvation. Proven by His resurrection.
Resurrection Day is my favorite Holy Day. Our Wounded Warriors celebrate their alive day. Not the same but precious none the less.