Jesus also said we are all the children of God. He seems to have liked playing word games making statements that can be interpreted in multiple ways.
What is not in question is who Jesus' mother is. Jewish religious law thought things out, and realized the mother identity of a baby is rarely in question, certainly not in the same way that the father's identity can be in question. Jesus' mother was Mary, a Jewish woman.
And Peter's parents were both Jews. All the original disciples were Jewish. Even the Christians that came after Jesus were all Jewish. Paul was originally Saul, and wanted to be a Jewish priest. Barnabus was a Jew from Cyprus.
There began being more and more Gentiles(non-Jews) who wanted to Christians. At first they were required to convert to Judaism first, but then one night Peter had a dream about unkosher food falling from heaven, and it was decided Gentiles could be Christian. Then when the Jewish Temple was destroyed, and the Jews exiled, it became clear that there was no center of Judaism to convert, and Christians finally broke away from Judaism.