Good post. The one real pearl of wisdom that resonated in your post is that your mind in many ways still feels young. When I was in my 30's I looked at men in their 60's as just plain old. I figured they knew they were old, they acted old, they felt old and they just settled for less.
Although I am not racing anymore, I don't feel like I thought an old person would feel. In some ways I feel less old not racing - racing and slowing down makes you have to confront the reality of aging. Not racing allows me to continue the denial of aging. "Well maybe I still could do it if I trained hard"
Sometimes denial is a good place to be.