I have a 13" Smith & Worthington Mystic saddle for my almost four year old daughter. She only weighs 37 pounds. I had to buy it new, as I could not find a used one (of any brand) in that size anywhere!! She's had it for about a year now. Her little butt is not doing anything to break it in. There is no one at the barn that is tiny enough to ride in it. Any tips on how to help it get a little softer?