Actually, Mary Magdalene was the first witness but the male disciples didn't believe her.
This is according to a Catholic version of the bible:
Mark 16: 9-11
Jesus Appears to Mary Magdalene
9 Now after he rose early on the first day of the week, he appeared first to Mary Magdalene, from whom he had cast out seven demons. 10 She went out and told those who had been with him, while they were mourning and weeping. 11 But when they heard that he was alive and had been seen by her, they would not believe it.