I think spelling out the context here is key. One of the aspects I love about this forum is that everyone is able to consider an outfit within the context of the poster's personal style, life, event needs, etc - or to know enough to admit when they are biased. Knowing what Rita has worn to this type of gathering in the past also helps me gauge whether this meets her (not my) needs in that context.
To me, this dress is completely appropriate for the purpose it would serve! My only concern is whether it's fitting correctly.
It's fascinating to have these glimpses into other people's lives and cultures and I'm so thankful for that. I'd love to go to one of these parties too!