Well done on and on 🙂
I’ve done a few centuries on small wheel bikes. Most people underestimate them.
The first was on a Dahon Boardwalk, just to see if it was possible. My memory of that ride is that unyielding seatpost turned the rest of the ride into posterior hell after about 70 miles, but that was on rough roads in the north of Queensland.
It was much more comfortable when I did a century on my Dahon Hammerhead which has a suspension fork and a Thudbuster.
The nice thing about a folding bike is that piking out is always an option. Just tuck it under your arm and get the bus/train home, or cadge a lift. 🙂