I don't think Jesus really cares that much about His birthday. But just when do you think it was ? I really don't go with December myself. Since Elizabeth (John’s mother) was in her sixth month of pregnancy when Jesus was conceived (Luke 1:24-36 Luke 1:24-3624 And after those days his wife Elisabeth conceived, and hid herself five months, saying, 25 Thus has the Lord dealt with me in the days wherein he looked on me, to take away my reproach among men. 26 And in the sixth month the angel Gabriel was sent from God to a city of Galilee, named Nazareth, 27 To a virgin espoused to a man whose name was Joseph, of the house of David; and the virgin’s name was Mary. 28 And the angel came in to her, and said, Hail, you that are highly favored, the Lord is with you: blessed are you among women. 29 And when she saw him, she was troubled at his saying, and cast in her mind what manner of salutation this should be. 30 And the angel said to her, Fear not, Mary: for you have found favor with God. 31 And, behold, you shall conceive in your womb, and bring forth a son, and shall call his name JESUS. 32 He shall be great, and shall be called the Son of the Highest: and the Lord God shall give to him the throne of his father David: 33 And he shall reign over the house of Jacob for ever; and of his kingdom there shall be no end. 34 Then said Mary to the angel, How shall this be, seeing I know not a man? 35 And the angel answered and said to her, The Holy Ghost shall come on you, and the power of the Highest shall overshadow you: therefore also that holy thing which shall be born of you shall be called the Son of God. 36 And, behold, your cousin Elisabeth, she has also conceived a son in her old age: and this is the sixth month with her, who was called barren.
American King James Version×), we can determine the approximate time of year Jesus was born if we know when John was born. John’s father, Zacharias, was a priest serving in the Jerusalem temple during the course of Abijah (Luke 1:5 Luke 1:5THERE was in the days of Herod, the king of Judaea, a certain priest named Zacharias, of the course of Abia: and his wife was of the daughters of Aaron, and her name was Elisabeth.
American King James Version×). Historical calculations indicate this course of service corresponded to June 13-19 in that year ( The Companion Bible, 1974, Appendix 179, p. 200). It was during this time of temple service that Zacharias learned that he and his wife Elizabeth would have a child (Luke 1:8-13 Luke 1:8-138 And it came to pass, that while he executed the priest’s office before God in the order of his course, 9 According to the custom of the priest’s office, his lot was to burn incense when he went into the temple of the Lord. 10 And the whole multitude of the people were praying without at the time of incense. 11 And there appeared to him an angel of the Lord standing on the right side of the altar of incense. 12 And when Zacharias saw him, he was troubled, and fear fell on him. 13 But the angel said to him, Fear not, Zacharias: for your prayer is heard; and your wife Elisabeth shall bear you a son, and you shall call his name John.
American King James Version×). After he completed his service and traveled home, Elizabeth conceived (Luke 1:23-24 Luke 1:23-2423 And it came to pass, that, as soon as the days of his ministration were accomplished, he departed to his own house. 24 And after those days his wife Elisabeth conceived, and hid herself five months, saying,
American King James Version×). Assuming John’s conception took place near the end of June, adding nine months brings us to the end of March as the most likely time for John’s birth. Adding another six months (the difference in ages between John and Jesus) brings us to the end of September as the likely time of Jesus’ birth
American King James Version×), we can determine the approximate time of year Jesus was born if we know when John was born. John’s father, Zacharias, was a priest serving in the Jerusalem temple during the course of Abijah (Luke 1:5 Luke 1:5THERE was in the days of Herod, the king of Judaea, a certain priest named Zacharias, of the course of Abia: and his wife was of the daughters of Aaron, and her name was Elisabeth.
American King James Version×). Historical calculations indicate this course of service corresponded to June 13-19 in that year ( The Companion Bible, 1974, Appendix 179, p. 200). It was during this time of temple service that Zacharias learned that he and his wife Elizabeth would have a child (Luke 1:8-13 Luke 1:8-138 And it came to pass, that while he executed the priest’s office before God in the order of his course, 9 According to the custom of the priest’s office, his lot was to burn incense when he went into the temple of the Lord. 10 And the whole multitude of the people were praying without at the time of incense. 11 And there appeared to him an angel of the Lord standing on the right side of the altar of incense. 12 And when Zacharias saw him, he was troubled, and fear fell on him. 13 But the angel said to him, Fear not, Zacharias: for your prayer is heard; and your wife Elisabeth shall bear you a son, and you shall call his name John.
American King James Version×). After he completed his service and traveled home, Elizabeth conceived (Luke 1:23-24 Luke 1:23-2423 And it came to pass, that, as soon as the days of his ministration were accomplished, he departed to his own house. 24 And after those days his wife Elisabeth conceived, and hid herself five months, saying,
American King James Version×). Assuming John’s conception took place near the end of June, adding nine months brings us to the end of March as the most likely time for John’s birth. Adding another six months (the difference in ages between John and Jesus) brings us to the end of September as the likely time of Jesus’ birth
(also if they portray a female angel, it's in error too).