In the book Scared Origins of profound Things states: "For two centuries after Christs birth, no one knew, and few people cared, exactly when he was born.

So why didn't Jesus disciples celebrate the birth of Christ? Well as said in The World Book Encyclopedia, the early Christians, "considered the celebration of any one's birth to be a pagan custom."
So even if they new the birth date of Jesus they probably wouldn't have celebrated it for that reason, and if they did celebrate it, well it would have been mentioned in the bible, but its not. The only mention of celebrated birthdays in the bible are of two rulers who did not worship or believe in God.

Now birthday celebrations were done in complete honor of pagan deities, take for example the 24th of May the Romans celebrated the birthday of the goddess Diana. May 25th is the birthday of their sun god, Apollo. So birthday celebrations is a Pagan custom and not a Christian one.

Ancient Romans and Greeks believe that a spirit attended the birth of each human and protected the person throughout the human life. Superstition? YES.
Early Christians were not superstitious so this could be another reason why Jesus disciples did not celebrate his birthday. Above all they knew that God would not be pleased with his son being connected with superstition.

So why is Christmas celebrated today?

it wasn't until hundreds of years after Jesus life on earth that people started commemorating the birth of Christ on the 25th. But that is not the date of his birth, evidently it took place in October. If you read about the birth of Christ in the bible it mentions that shepherds and their flocks were in the fields, so that could not possibly be the Month of December. Why? Well in Bethlehem the place of Christs birth. The Jewish Month Chislev (November/December) was a Month with cold and rainy weather. The Month after(December/January). it saw the the temperatures drop,so it would probably have snowed.

Even the bible writer Ezra showed that chislev was indeed a Month known for its rainy and cold weather.

Now in the bible it mentions that shepherds were attending to their flocks during the birth of Jesus Christ. The Bible writer Luke even mentions that shepherds were living outdoors to watch over their sheep. So its pretty clear that Jesus was not born in December because shepherds were living outdoors to attend to their sheep at night.

so why is the 25th of December chosen as the birth date of Jesus Christ? Some who later claimed to be christian likely wished that the date go hand in hand with the pagan Roman festival marking the birthday of the unconquered sun. During the winter pagans held ceremonies to get back the source of warmth and light to return from its distant travels. December 25 was thought to be the day the sun began its return. In efforts to convert pagans, religious leaders adopted the festival and tried to make it seem "christian".

Pagan roots of Christmas have always been recognized. In the early 17th century Christmas was banned in England and in some American colonies but the practice was soon back and is still in full practice today well with new additions and has become a huge holiday celebrated worldwide.

People today though non believers of pagan worship celebrate Christmas not as the birth date of Christ but as holiday to spend time with family and friends. but why do Christians still celebrate knowing that its a pagan holiday? It leaves us wondering whether Christians are true worshipers of God or Pagan worshipers. But that's up to you to decide that is if you are a true christian or not.