Well, as far as we know, we are all diferent aspects of Luca.
https://en.wikipedia.org/wiki/Last_universal_common_ancestor
That what we consider us (our conscient self) its alive is not that clear. Cells on the other hand are clearly alive, but their age is not that clear.
If a bacteria divide itself in 2 "new" bacterias, are they really new? Their components are the same.
If they are new, the age of an animal composed by cels should be the age of the last divided cel. Maybe a week or two? And if they are new, did the previous bacteria died when it divided itself in two new ones?
If they are not new, then both of them are of the age of the previous bacteria, which is of the age of the previous one... untill we reach Luca. Then all known life in the planet would be the same age, since we are all Luca that actually never died.
Yeah, its an interesting topic.