Yes , it is tough. But , that's just the way it is. Probably finding a team that is better suited for your current ability might be the best option.
But you invited her on your team, which I assume means you believed she had the skill to play this level. Now, you're saying that finding another team that is better suited for her current abilities might be the best option. If she's not working hard, I get that. But assuming she did the work, what happened? Did you misjudge her abilities? Did you fail to develop her? Did you give her every chance to succeed (ie, let her bat in bracket games)?