how do you see how old you are?

[Zunymitshu]

thank you in advance.

[TheDale]

Been wondering the same after picking a character.

[lynxbird]

You can find a character's age in the game logs, along with their background and the date when you selected them.
The character ages 1 year every 144 in-game days, which is very slow.
Age only becomes a concern if you choose a character who is already very old.

The only downside of aging is that the character can develop the "Old" talent after age 60. This can be prevented with the "Forever Young" talent.