TLDR: I think age goes up by one every 121 and 2/3 hours. Someone with 1,100 hours would be 27 years old.
As you might know, the player starts at age 18 and gets older the longer their playtime is, but it seems not many know how long someone has to play to age up. Here’s how I think age works:
Every ingame day is 20 minutes (according to a forum comment I read). A year is 365 days.
So 365 times 20 is 7,300 minutes for someone to age one year, or an hour count of 7,300 / 60 = 121 and 2/3.
Here’s the hour count and age of my friend’s character:
Their hour count is around 1,100 and their age is 27.
1,100 hours is 66,000 minutes. Divide by 20 and you get 3,300 days.
3,300 divided by 365 is just over 9 years.
9 plus 18 (the starting age) comes out to be 27 years old.
Please tell me if I got anything wrong!