"Legion" has existed for approximately five Human years. A truly accurate measure is impossible due to the inexact nature of time in this location.

(The programs, of course, are in many cases much older: pieces of them date from before the morning war. But the specific consciousness that is Legion is actually very young. And they only really started to fully actualize as an individual shortly before they were killed in their home universe.

...She probably thought they'd be older than that, didn't she?)