Reaching Mars in 4 years is the goal. He has always thought that was a stretch goal, as has been clear on every single presentation he has given on the topic. (BTW, NASA has a stretch goal of 2024 for landing people on the Moon; they acknowledge it is a stretch goal, and it probably also will be years later. Does that make NASA liars?)

But I'd say there's a greater than 50/50 chance of SpaceX landing people on Mars in Musk's lifetime. But that's not even THAT remarkable... Their actual goal (self-sustaining Mars civilization of at least a million people) is 5-6 orders of magnitude grander than that, and almost certainly won't occur in Musk's lifetime. Musk acknowledges that.