What's your text for that? In the Gospels, the people of Nazareth refer to Jesus as "Joseph's son" or "the carpenter's son." There's no indication I'm aware of that Jesus was not considered the legitimate son of Joseph.
DOH!!! You are right. Shame on me!!! I am supposed to know this stuff. Ok, According to Matthew God told Joseph to flee to Egypt to wait Herod's deathand they stayed there till Herod died, so obviously he died within a few years. When Herod saw he had been decieved he got ticked off and thats when he ordered the male babies in Bethlehem to be slaughtered, between birth and two years of age. Then Joseph took them to Isreal and then Nazareth. In Luke it says that Jesus's parents went every year to Jerusalem for the feast of the Passover and they went when Jesus was 12. It does not say in Luke he had his Bar Mitzvah though. Do you know where it says anything about that?
Whoa there! Getting knocked up after the betrothal but before the wedding was scandalous (it cast aspirations on the bride and groom's ability to control themselves) but in no way did it make the child illegitimate. They were already legally bound.