Am I ready for a century?
Its not the distance, its the time on the bike.

Assuming this is not a solo ride, you'll be riding with other people either in a proper rotating bunch ride, or just on the same road/direction as them.  This alone will increase your overall speed by as much as 20%.

If you can be seated on a bike for 6 hours in a day, you can do this ride.

You will need to eat regularly.  For me thats "something" every hour, a gel or chocolate or a bar or some sort.  Or bananas, some people like them.

Water is also big - One plain water bottle and one with electrolyte mix added.  You will be able to top-up water bottle at the filling stations, for 161 km I'd expect 3-5 total stations along the route.  Check the map, but plan for one to be missing - its happened to me.

Filling stations are a rest point - you can get off the saddle while doing bottles, drink and eat, and go again.  Personally, 5 mins is plenty, but on a really long ride I like a 15 minute at somewhere over 50%.