Age is a number, plain and simple, but society and culture can put pressures on that are hard to surmount. I dated a 37 year old when I was 19 and married a 30 year old when I was 50. In between there were relationships with both older and younger. I have never let a persons age define how I felt about them. There are way more important things to consider.
I'm sorry, I don't understand the question. How important is old age for likelihood of heart attack, or winning an Olympic medal in the 100 yard dash? Both, I'd guess. Sex? A relationship? And what does being interesting and/or attractive have to do with any of these? Also, how are you defining 'old age'? Before she died, my 85 year old mother defined it as anyone over 90!