A century is approximately three billion seconds, the second being variously defined across history as a multiple we find convenient of whatever universal natural constant we can most precisely measure -- most recently 10 billion or so of a specific type of vibration of cesium atoms.

All the other stars and planets would have the same experience, though their local orbital periods might result in different units of expression being more convenient.

Of course, as we leave our galaxy they would also be in significantly different reference frames and perhaps experience the rate differently as a result. We are assuming that, statistically, our relative velocity is not special and they see roughly the same relationship between red shift and distance that we do.