A Harvard grad driving around town.
It was clear in his ministry that Jesus came for the lost sheep of Israel. He even said so:
Matt.15  He answered, "I was sent only to the lost sheep of the house of Israel." So perhaps you could claim that baptism made him a christian. But he had no intention of starting a new religion. He just wanted to reform Judiaism.
My understanding is that Judaism wasn't formed until after the collapse of Jerusalem in 70 AD. At the time of Jesus there were different religions of the Jewish people, which included the Pharisees, Sadducees, Essenes, Nazrenes, Qumran community, and probably others that we know little or nothing about.
Perhaps Jesus wasn't interested in starting a religion, but I personally think that is unlikely. The reason is that there is good reason to think that he did preach in Samaria since this would be embarrassing to the original Jewish sources of the Gospels and its inclusion usually means that the belief was so wide-spread about Jesus' ministry that it needed explanation and could never be left unmentioned as to why he went into those non-Jewish areas.
I think Christianity actually started with the conversion of Saul to Paul and the subsequent transformation by Paul of Christianity into a religion compatible with totalitarian rule.
Well, what is probably indisputable about Jesus' ministry is that he was not a Zealot who opposed Roman rule. Given his emphasis in the Gospels on rewards being in Heaven for suffering, it would appear that Jesus taught to bear the suffering that came from all areas (e.g., Roman rule, taxes, poverty, etc). This is not too much different from Pauline doctrine. Although, Paul gave indications in his epistle to the Romans that the government is instituted by God to administer the laws, of course Jesus might have felt the same way (and if he didn't feel that way there is nothing I know of which says so).