Hello Elisha, you would need to contact the manufacture directly to find out way them do not make small size fins. I do not know where you would find a size 4.5-5.5 free diving fin. We do carry the: http://www.scuba.com/scuba-gear-20/014837/Mor-Fin-Natural-Delfins.html
that I think would work for you. If you have any other questions please feel free to give us a call at 1.800.347.2822.