To me it doesn't matter that Jesus Christs' birth probably wasn't on Dec. 25. What Does matter is that He Was born -- His birth is Very important and I enjoy celebrating His birth. His virgin birth And His bodily resurrection. The fact that He, Jesus Christ was truly God's Son, makes all the difference in the world for our salvation.
God's Word / Bible gives us two narratives of His birth -- Matthew and Luke. In wonderful detail. So -- Do take time that one day a year To celebrate.
We're not told to celebrate birthdays or anniversaries every year, either. But I'll bet we do. Well, those of us who are married and have children certainly do.