How long is a sim a young adult/adult?

"kiwi84;d-1005248" wrote:
I am trying to decide at what age a sim will go over to be an adult from young adult, and I think for me it would be about 40 years old. Only problem I feel like the sims make the adults look so much older than 40. How do you define the ages in sims 4?

I don't think the sims make adults look older than 40...It's really the player who decides that with clothing, hair, and face details. Depending on the sim, I will change their wardrobe to be a bit more classy, polished, and sophisticated to make them older. The aging wrinkles I use all the time. The black and brown gray hair swatches comes in handy as well. I do this most often for a sim who has teenagers because I do not like their parents looking the same age as them so I make sure I age them visually as much as I can while they are in the adult phase.