Isn't the goal to land on the moon first? That will also need on orbit refuelling. I know that SpaceX move fast and multiple launch facilities could well be up and running in a couple of years but I still think this is optimistic even for Musk.
I could see a moon landing in 3 years but not Mars. That's at least 5 years away.
However I will be delighted to be proven wrong. 😁