Nice job. Average speed of 15.6 mph is fantastic for a century.
Your nutrition on a century is very similar to how i approach a long ride. Usually eat real food until late in the ride when a little caffeine and sugar ( Mountain Dew in my case) perks me right up for the kick at the end.
Last long ride I was on was July 2015. Took me 11 hours in the saddle to complete 125 miles. Very slow, but had a few mountain passes on the route.