Firstly, I have no interest in looking younger - I'm very happy to be getting older and wiser and happier in my (wrinkly) skin. I don't want to look like a 20 year old anymore and I am suspicious of a culture that tells women they should.
The other part of the OP that interests me is the 'why wouldn't you want to look your best?' question. I think I look best in heels, shapewear, underwired bra, fitted and tailored clothes with my hair professionally done and yes, make up on but I don't do all that every day because it's not comfortable and I don't want to feel hot and restricted with sore feet all the time. Today I'm in a loose linen dress, a non-wired bra, I let my hair dry naturally so it's in wild curls - I did put make up on: I pencilled in my invisible brows and put concealer on my undereye shadows. I look like a hippy in a shapeless sack and Birkenstocks, though relatively awake and fresh-faced. I feel so comfortable and that is a trade-off worth making for me.
I have teenage boys and I do wonder what it is about our society that means they can go out with their faces just the way they are, but if I had daughters they'd likely be putting make up on. I don't think it's right, and I say that as someone who likes make up even if I don't do a full face every day. I especially love bright lipstick, though I suspect it's quite unfashionable right now.
I really love to get dressed up and done up - sometimes, so it feels special and fun. I'd hate it if it felt like a daily obligation. And I hate that it is a sexist expectation, even if I myself participate in it.