A Metric Century requires some carbohydrate loading, probably for a week before the event. I prefer pasta the night before, but others have other choices. I do not like bananas, but advise them the morning before a ride. I personally prefer nutella on toast, because I loathe either bananas or eggs. During the ride, keep your hydration up, and eat beans on toast to keep the other riders respectfully away from your wheel. As you have today, tomorrow, and Friday for loading carbs, eat lots of pastries, breads and pasta, and hydrate well each day. Enjoy your ride!