Increase your mileage little by little each time and you will be fine. The challenge doesn't start until you hit 18 miles (30 km), that is when runners start to bonk and hit the wall. But I am sure you can beat them all. Add oil ar!!
It is 6am here, 31C but cloudy. I can't afford to miss this opportunity with a cloudy sky. I'd decided to tape the Tour de France (I know Carlos Sastre is going to win anyway) instead of watching it live. I am about to leave the door for a slow 12 miler (20 km).