Old Age Question

Why does the magic of the youth die with each realist idea I accept as the new truth? Did I age or mature when I let a child's play be replaced with a memory? How does one age well? Is there a way? Is there a guide? A mentor to walk me through the path ahead which I don't want to know. Let me have my surprises - my joys and sorrows as they come and go. Life as fleeting as it is.