Can we not "look" our age and what not

My dear friend Susie is turning 54 tomorrow and today she seemed, well, a bit sad. She told me that when she turned 40 people would say she doesn't "look" her age at all. So now she feels she is "looking " her age. First off, Susie is a beautiful person, not just on the outside but also on the inside. And the lines in her face and the gray in her hair is part of who she is. It shows her journey to the place she is at now. So what is with this whole "look" thing anyway. And what is 40 or 54 supposed to "look" like? I guess I don't care if I "look" 40 or 50, I would just like to feel like 18!