Not building a -14, so don't know what you're joining. Some structural joints depend on the expansion of the rivet to lock the parts against movement in shear. Bolts & screws don't typically fit tight to start, and the diameter shrinks slightly when torqued.
I made a similar mistake (over countersunk) on my spar, & Van's ok'd going to larger rivets as long as I avoided knife-edge at the bottom of the countersinks.