If you take away that privilege, she's likely to react. Research suggests that authoritarian parenting does not really benefit bipolar children.

Maybe you should try working out a deal. If she does _________, she can go to her dance lesson. If you take it away all together you're likely to just %#@&#! her off and make her even more defiant.

Besides, socializing is good for kids. Don't dish out harsh consequences just because you're frustrated.