I think age is definitely a number, it's all to do with the heart and mentality. For myself, not having kids means I don't have to behave as a grown up all the time and be a parent role model. Not having to worry about kids health, education, well being and safety, and the financial burden of bringing up a kid ( I hear they can be quite expensive 😅) probably helped to keep my mentality younger all these years.
The only time when I'm reminded of my real age is when my vision starts to go blurry or when I have aches and pains. Those were things that happened to my gran when I was a kid, and it didn't seem like that many years ago!!
We would certainly be richer if we hadn't had any. 😅 I wouldn't change it for the world, though. My youngest helps to keep me feeling young as well now. She expects me to keep up with her. 🤣
It's like when they say "20 years ago" and you think "the 80s?" Time just flies past once to reach adulthood.