How Do We Measure the Age of the Universe?

The universe is 13 point eight billion years old according to clocks that are not in motion relative to the cosmic microad background radiation. But if our clocks were not at motion relative to the c m b, it would be a tiny little bit different than this. And we're actually moving through the c m b at several hundred kilo ters per second. So what that means is that there's no absolute reference frame for measuring age of cosmos. It just happens to be the one in which that stuff is at rest.