My first ukulele was a 1950s Harmony soprano my father-in-law gave me. Much too cramped for my (also short fat) fingers. So I bought a tenor. Then another tenor, then another, then a couple-three concert sized, and back to sopranos, and another tenor.
Playing the larger sizes was very good for my fingering and technique, and as I started playing the banjo ukes (soprano size), I was feeling more comfortable. When I got the Ohana Vita Uke, which is a soprano scale neck on a concert size body, I started playing it much more often, understanding a bit more about the pressure I use on the soprano strings, vs. the tenor and concert strings.
While my Tenor Sceptre is my VERY favorite uke, the Ohana Vita Uke has become the daily pick-it-up-and-strum while at the computer uke - and my fingers don't cramp up like they used to.
So my advice is simple: keep the soprano, but get a tenor. Get comfortable on the tenor, but pick up the soprano every 3-4 days and use it. After a few months, if you don't find yourself getting very comfortable on both, then decide which one is best for you.
Good luck!
-Kurt