The real Phantom Menace.
This is actually an interesting question. How is age handled in a space-age civilization? Someone born on one planet could be 10 while on a different planet they’d be 50 in the same timeframe. What if you spend part of your life on one and the rest on another? It’d be inconvenient to use one planet’s ‘day’ as the standard, as they’d all be different lengths…
In Star Wars, a Galactic Standard Year corresponded to the time it took Coruscant to orbit it’s star once, 368 standard days.
You can tell it’s a crazy sci-fi galaxy because the year is 3 days longer than ours. They really went wild with these ideas sometimes.
What, laser-sword welding space wizards weren’t crazy enough for you?
Use a unit of time based on universal constants, like seconds, an earth year is roughly 31.5Ms.