The Moon is a terrible "start" for Mars. They are very different places, and require solving very different problems. In many ways, Mars is a lot easier (the atmosphere can do a lot of the work of slowing you down, you have the raw materials to make methane (the rocket fuel SpaceX will be using), etc).

People tend to think of the Moon as a "staging point" on the way to Mars, but in reality, it would be a significant detour.