Edit: celestia’s hair is changed to have white streaks
★★★

Twilight is crowned Princess of Friendship and Celestia and Luna leave up the duties to Twilight and Spike to rule Equestria.

NOTE: Alicorns age are almost in tune to the people they love and cherish. Princess Celestia and Luna are almost immortal because of their love and care for Equestria and her ppl. This does not change even during retirement.
(ex. Twilights age is tuned to her friends, Candace to her husband etc)

Celestia funds alot of charities and small buisnesses and goes to parades alot, she's a very social mare who likes to get into everyones buisness. Nothing has really changed in her social status and some people still call her Princess Celestia, much to her dismay.
She fell in love with a humble teacher in ponyville, Cheerilee, after going to one of their school plays.
(they have a child named Sunny)

Luna isnt very out there as Celestia, recently she's gotten into writing and has become a rather famous author. With the pename "Night-Mare Ink"
Publishing various works based off the dreams she encounters.
Luna isnt too focused on relationships.
★★★