You have a magic pill, which de-ages you by 20 years. You can take it once in your life only, so long as you are at least 20. What age — past, current or future — do you reckon is best to take it?
I'd take it today. I'm in my 50s, I'm an endurance athlete (I race bikes) and the calculus looks like: if I wait 20 years I get to experience body-age 50-70 twice, but if I take it now I experience 30-50 twice. Living my prime twice is better than enduring my decline twice, thanks