The decorating of eggs pre-dates the story of Jesus by some 3000 years. Originally it was to celebrate Ostara or the festival of Ishtar (pronounced “es -tar” in Arabicm and later refered to as Oestra by the Celts) the Goddess of fertility and prosperity.
The symbol of the egg as a sign of fertility carried over int the Jewish religion, where among the orthodox it is still traditional to place a decorated in the water of a female baby’s first bath in the belief that this will cause her to become a good mother when she grows up.
Incidently, in the original Babylonian tradition, the shell of the egg was originally decorated with blood from the infants unbilical cord at birth. Then the rabbit or hare, which was the sacred animal of of Ishtar / Oestra, was thought to collect the decorated eggs and bring them to the Goddess to be protected.