As the user of this app I was thinking socially active fun-lowing females of all ages; probably living in a big city going out at least a few times a week; and for whom enjoying the company of girlfriends is an important part of their lives.
You might want to work on finding another descriptor. I just checked Urban Dictionary and every definition they have agrees with my general understanding that "party girl" doesn't really refer to a gal who likes to hang out and socialize with her gal friends. It generally suggests sex, drugs, and low personal standards.
http://www.urbandictionary.com/define.php?term=party%20girl
Edit: You might try looking for a word more like "socialite".
