I'm 22 and starting to notice bags under my eyes and lines around my lips. You'll notice different changes depending on culture, ethnicity, eating and lifestyle habits, etc.
My face didn't really change at all from 16-18. Only now at 20 am I starting to see subtle changes in my face. It's a pretty obvious difference when I compare pics from now to pics 4 years ago, but nothing major (20 is still really young obviously), just a general impression that the boyish adolescent look is kind of going away. I also grow noticeably more facial hair now a 20 than I did only 2 years ago. No signs of balding, yet, thank god.