how tight are you in most size 14's? thats going to be your best bet to finding out, and can try to go to a shoe store and just try on a few size 13's, not buy anything but just see in a similar shoe style if they fit or its a total nope.
I'm Size 12-13, it varies by shoe, some I can fit 12 no problem others, nope gotta go 13. It can Vary saddly and you do take a risk buying the smaller of the two sizes.