Memoji Create/Edit Updates in iOS 14
I looks like they added more options to make your Memoji look better. Well at least from when I originally created mine, and that was likely back in iOS 12. I think I updated in iOS 13 though. At any rate, there are many more options now, including aging options. The aging options still don’t add enough age for someone my age though!

But it least my Memoji now looks like a 40 something guy with grey hair rather than a 20 something guy with grey hair!