There will never be a colony on Mars. Not in the way we think about "colonies".
For starters it's too cold, too dry, atmosphere is too thin, and there's no reasonably sustainable power source.
But all of that is irrelevant because there's no magnetic field. So radiation. So unlivable.
There's also no point in a colony there. If life ends on earth it ends on Mars. There are no materials there we want. It offers exactly nothing we can't do better here, for much less money.
Will we land on Mars? Sure. There's always the goal of being first. But live there? No. Unsupported by earth? Very much no.
I personally believe that the legacy we send to the stars will be silicon.
Robots have landed on Mars. Maybe they will even figure out how to use minerals on Mars to build more of themselves. It is plausible to me that as far as space exploration is concerned that it will be autonomous within a few hundred years.
'..it might be assumed that the flying machine which will really fly might be evolved by the combined and continuous efforts of mathematicians and mechanicians in from one million to ten million years- provided, of course, we can meanwhile eliminate such little drawbacks and embarrassments as the existing relation between weight and strength in inorganic materials. No doubt the problem has attractions for those it interests, but to the ordinary man it would seem as if effort might be employed more profitably.' Oct 9 1903