The Shoeless Jane 13" Fastpitch Softball First Base Mitt: 1300FPFB is meant for a female fastpitch player. I would recommend the Shoeless Joe Professional Series: 1300FBTT First Base Mitt for a men's slowpitch player.
This Shoeless Jane 13" Fastpitch Softball First Base Mitt (1300FPFB) is going to be a first base mitt, so you can only use this glove at first base. The other option with a lot of reviews, the Shoeless Joe Shoeless Jane Fastpitch Series (1300FPBW) is a normal fielders mitt. So the two gloves are going to be pretty different, what she would want is depending on what position she would play.
The best glove for a SS to use will really be dependent on the player's age as well as personal preference. For sizing considerations we would recommend using our glove coach feature: