Earlyish 60s here.
I have never been particularly interested in my appearance but really don't care much now, in the sense that clean and comfortable are my priorities.
Very uninterested in what other people think about me. Plenty of confidence, so I am generally pleasant, warm, friendly, but won't take shit from anyone.
I treat my health and my body as a project. If I don't care for it, no one else is going to step in. If someone is offended because I won't eat their cake or drink alcohol then that is very much not my problem. "Looks delicious but none for me, thank you".
If it offends people (and I know of two or three people who it does) that I am very fit, very active, slim, then they need to make changes to their lifestyle, putting the effort in, not make snide comments to me. I looked at female relatives who put on weight after the menopause and thought "nope, not doing that." My body, my choice, and yes, it takes daily sustained effort.
Older age also brings the wisdom and experience to put things in perspective. Most stresses or problems wont be so bad in 5 minutes/days/years time. Building up resilience is essential.