There is a lot of good advice in this thread. I'll add my .02.
The type of bike you ride is secondary as long as it fits, is mechanically sound and has fairly skinny tires at max air presures to roll free.

The two most important things for any century are: Preperation...build your base mileage gradually and rest when unusually tired to avoid training injurues. 2. On the bike.. Drink and Eat the energy replacement fuels of your choice waaaaay befor you get thirsty or hungry particularly during the first half of the ride.

As long as you pace yourself to your level of training, (enjoy the adenalin rush at the start of the ride but control it and do not get sucked into a super high early pace that your body is not use to) and stay hydrated/fueled, you will have a great time on your century. Good luck and have fun.
Bill J.