Moses and those with him were Israelites, not Jews.
Being trained in Judaism, she immediately admitted that I was correct.
(Interestingly, the partitioning of the Old Testament kingdom of Israel into Israel and Judah after the death of Solomon actually moved the identifier "Israel" away from Judah. Israel became [so to speak] the group which would later be the Diaspora!
Alas, I never got a chance to follow up with the Jewish girl about the eschatological implications of this.)