What would Jesus of Nazareth think about Christianity? Imagine how you'd feel if you had the Bill and Ted experience of discovering that in the future you are worshipped as a god!
(I know the evidence for the existence of Jesus is slim, but I think that what there is--Paul of Tarsus writes about speaking with Jesus's brother, James. Flavius Josephus mentions early Christians. Some of the people and events described in the Gospels are known to have existed or occurred--is enough for me to guess that he probably did exist. Etc.)