Those outposts on Mars won't fare any better when the sun goes nova - it is also just a question of time.
We are much better off concentrating on developing technology to detect and alter the trajectory of asteroids (it just takes a little nudge if you do it far enough in advance) than we are trying to colonize Mars.
Yikes! The sun will not go nova - if it even does - for billions of years. Moreover, the Sun going nova is a theoretical possibility, not an actuality. Large astroid strikes are real.
A major a astroid/comet strike could happen at any time from today to several hundred years from now (but likely somewhere around or before 2060 when the Earth is due to pass through a major part of the Taurids debris field - last time it ended the Ice Age and 1000 years later began the Younger Dryas, a period colder than the Ice age)
A nudge? Takes more than that - you’ve been watching too many simulations. Besides, there is no way to know that today’s ‘little nudge’ course change will not create tomorrow’s disaster. Changing the course of an astroid is not something to be undertaken lightly as there is no telling what objects it might encounter on the new course or what might come in from the outer system to hit it.
The worry is not the rocks we can see but those we cannot - that come in sunward with little or no warning - and of which there have been several recently passing between Earth and the Moon on a day or more notice.
Try to think ahead, as if we were to colonize Mars, do you imagine that colonization would end there? There are all the other bodies which could not only be colonized, but be virtually immune from the-billions-of-years-in-the-future-theoretical-sun-gone-nova.
Like I said species survival is too expensive for some here.