So here you are, in your twenties, thinking that you'll have another 40 years to go. Four decades in which to live long and prosper.Bad news. Read the papers. There are people dropping dead when they're 50, 40, 30 years old. Or quite possibly just after finishing their convocation. They would be very disappointed that they didn't meet their life expectancy.I'm here to tell you this. Forget about your life expectancy.