I relate to this. I agree with Suz that it can be ageist/sexist to generalize, but I also think it's natural to reach for the things you used when you felt really beautiful, in hopes of achieving that look again!
For me, my early 40s have resulted in some big changes to my makeup look - I was shocked once when I put on liquid eyeliner in a way I'd done many times in the past (a cat eye style) and it looked ridiculous because my eyes have become more downturned and hooded as the years have passed. It was a process for me to accept my changing face and update my makeup techniques to suit it. I think it would have been a shame if I'd just stayed stuck in that battle to wear what I wore, and I think that's maybe what this idea is getting at - that there are surely some women (and men) who just never accept the changes, and thus stay stuck in the past.
I also think probably there are a lot of people who just get busy with other things and choose not to follow/worry about their look, so they can end up looking dated. More power to them as long as they are happy!
I couldn't say when I "peaked" physically; all I know is I look back at photos that I never thought much about and now think, "damn, I was cute!!". So I choose to assume that 20 years from now I'll look back at 45-year-old me and think the same thing; therefore, I choose to believe I'm pretty damn cute now, even when I don't feel that way
Synne, I think you'll find your makeup style will evolve wonderfully - you have amazing style and a pulse on what's current! Just give it time!