Agreed. Except that Paul didn't really start or invent Christianity. He co-opted it and morphed it from what it was into something that more mirrored Roman totalitarianism.
On the one hand, him being a citizen of Rome and having easy passage along the Roman road system because of it allowed Christianity to spread.
On the other hand, Paul never actually knew Jesus. He had a vision of/encounter with him on the road to Damascus something like 20 years or so after Jesus was crucified but he never sat and learned at Jesus' feet. This is very clear when you compare the teachings and sayings of Jesus with the letters that Paul wrote. Paul often contradicts the (spirit of) Jesus' teachings. The fact that Paul's conversion led him to stop persecuting Christians proves that Christianity as a religion already existed before Paul ever had the vision/encounter.