I think it would depend on the circumstances. Is it a holiday party? Is it the only family party you have each year where everyone comes together? Does she "really" hate you? There are too many variables to consider with these types of situations. However, I do believe that going with your gut on this would be the best way to handle it. If you do not feel like going, feel like it may turn into a catastrophe, then stay home. If you want to go with some armor on and brave the evening, then you go girl!