It's actuallt EETA79001 to which Bounce has been matched. That space rock has an exposure age of 0.65+-0.2 Ma and a terrestrial residence age of 0.32+-0.17 Ma, giving a total age since ejection of ~1 Ma

It still brings home the very low weathering and transport rates on modern Mars. In 1 million years time, the rover tracks may still be detectable across the plains of Meridiani and Gusev (Though they will begin to change - note the wind "shadows" around Bounce)

If you beleive the most optimistic of the eccentricity/obliquity models, then 5 Ma ago things were different. Much of the surface appearance of Meridiani could have originated at that time and been "fossilised" since then.

And, for your interest, Bill Hartmann, Gerhard Neukum, and their respective groups have had extensive funding for many years to improve crater counting and age dating, and they continue to report steady progress in this area at each major meeting. Perhaps you should buy the Hartmann-Neukum book and go read it. Don't come back complaining until you've read and understood it.