See @pattar, LE does my “splaining” for me now, so you leave him alone!While I am not arguing that a baseball mitt is designed for a smaller ball, I am saying the mitt can be broken in for softball. If your daughter prefers the feel of the baseball mitt, go for it.
The two pictures are of my daughter's Liberty Advanced 1B mitt and my Rawlings GG Dick's series 1B baseball mitt. I bought the latter to catch for my daughter way back when she was throwing in the 40s. While the softball mitt is ever so slightly larger, the GG pocket is more than large enough to accommodate the larger softball. View attachment 27188View attachment 27189