Once you pluck up the courage- then a century ride WILL be done--As you have proved. But there are easier ways to do it than on on a heavy bike with wide tyres and on Crushed hardpack.

Well done but the Ride your age still has to be done

Now if you had announced that you were doing a ride your age ride and then went on to do a metric century and then a full 100 miles- then you would have progressed in the right order and could claim all 3.

Well done on achieving the 3.