I'm not going to listen to you, you're too biased against asteroids.

Edit: But you're right. I tried searching for the crater's age and couldn't find any primary sources. Though, I did find this:

http://www.space.com/2987-red-planet-double-team-nasa-orbiter-spies-mars-rover-victoria-crater.html:

Early estimates pin Victoria Crater at somewhere between 10 million and 100 million years old, but the rocks within the depression themselves are likely much older - as in a few billion years in age, researchers said.

And, uh, this:

http://www.holoscience.com/news.php?article=8p6ud5jc:

There are many unresolved problems with the impact-cratering model, which led the Irish astronomer, Firsoff, to express his dislike of the theory. However, no one has considered a better theory, electrical cratering…