Prior to my first century in Oct 2004 I rode the MS150 in April which had 90 miles on day 1 and 80 miles day 2. I rode often and long (max 76) to prepare for the MS150 and I felt fresh as a daisy at the end.
Then I started only wanting to do about 20 miles April-October since I used to wilt in the Texas Sun. I ran 4 times a week, so I was in good shape physically. The century went well until about mile 80. My knees began to swell, my back to hurt and it became a war of attrition. I made it to mile 102 (finish) but I felt it in every muscle.
Last year I did four centuries (July, August and two in September) and rode 100 miles total nearly every weekend from April on. I was able to put up good times, yet on three of them I still had to really push to get through. They were all hot, which isn't the best weather to have at mile 80 on.
I would say a century can be more mental than physical. If you want to see 100 miles you will find a way, barring a crash or true physical issues.
Amanda
2011 Specialized Epic Comp 29er | Specialized Phenom | "Marie Laveau"
2007 Cannondale Synapse Carbon Road | Selle Italia Lady Gel Flow | "Miranda"
You don't have to be great to get started, but you do have to get started to be great. -Lee J. Colan