Good luck. I remember feeling pretty nervous at my first century, too.

I'm sure there's not universal agreement about this, but my best advice is to make your stops short. Don't linger any longer than needed to grab some food, go to the bathroom and stretch. Especially on a ride that invovles some climbing, I find it much harder to keep my climbing legs if I stay too long at stops. This will also, of course, help you with the time cut off.

Stay on top of your hydration. While it'll mean more frequent potty stops, I would suggest having a big glass or two of water first thing that morning.

Let us know how it goes!