Thanks for the clarification Trip. I guess I haven't looked that closely as I barely see a difference between YA and Adult sims.
My females usually revert back to a previous age up hairstyle, but if I give them back the one they had for YA, they look pretty much the same, to me anyway. lol
But with your knowledge in hand, I went back and checked out my Sim Odette, before and after her Adult birthday.
After looking closely at several photos, I did notice a sharpening of her cheekbones, a more narrow jawline, and a hint of laugh lines around her nose and mouth!
So the difference, though subtle, is there between YA and Adult sims.
Though I wish they aged a bit more gradually between Adult and Elder as that transformation is usually quite a shock! lol