What age would you be if you didn't know how old you are?

Looking in the mirror a few years ago, I saw that, apparently overnight, loads of wrinkles had appeared on my cheeks. How on earth had that happened? And come to think about it, could that occasional twinge of pain in my thumb be like my Mum’s arthritis? Could it even BE arthritis? But if my body had arthritis in it and was showing wrinkles, that surely…