You're only as old as your birth certificate says. You hear a lot of stuff otherwise, and a lot of products are sold to make us think we look younger. We don't.
My experience of all this says if you can avoid work injuries or accidents, keep the excess weight off and consistently walk and exercise (and I don't mean being a lifelong gym rat), you can do okay. Genetics are crucial, and knowing a bit about your family helps a lot. You have to start early. I know I inherited my Dad's power of maintaining strength late into life. That's useful. I have to watch my conditioning as I come from a diabetic family. Those are the other genetics.
None of this is looks. I think we would do well to be aware of that. As you age, you look different, unavoidably. Even the sliced and diced stars give it away.
On a forum, we tend to be older and younger, as the humans in between are sometimes buried in responsibilities that take their time, especially in the US. In a gathering, older members deal with partial invisibility, a power we develop unless we're loud extroverts. People talk around us like we aren't there. That's odd. But it happens, and plastic won't fix that. It does work well if you become a people watcher. It's possible that since I was seriously ill as a kid, and constantly called an old soul when I was into my teens, I am well equipped to deal with age. I never did anything gracefully, so I don't worry about age and grace in the least.
Frankie Valli? Good for him. I recently watched a punk band reunion, the survivors of a band I'd really enjoyed 43 years ago. They looked like tortoises. But they still sounded like it was fun. That's the key to me. If you can still create, laugh and think, you're doing okay. Age'll get you, but be a moving target.