Contrary to the question's premise, the Star of Bethlehem traditionally has six points, not fourteen.
The six-pointed star is the Star of David (Magen David), a symbol of Judaism and the modern flag of Israel. In Christian nativity art, it represents the Jewish heritage of Jesus and the fulfillment of Old Testament prophecy.
The Star of David was not exclusively Jewish until the Middle Ages; earlier it appeared in various cultures as a decorative hexagram. Its association with the Nativity is a later artistic convention.