Translation:Is everyone going to this party?
I was taught 会 denotes the ability to do something, not a desire or necessarily a future action. For instance, to me, 我会游泳, means "I am able to swim." Whereas, 我要游泳 is "I will swim." So I don't think 会 is appropriately used. I was taught mainland 北京话, maybe this usage is Taiwanese. Was anyone else taught the same as me?
大家 = everyone. IF you're addressing a group you might say either "all of you" or "everyone" BUT the given sentence could be said to a single person asking if everyone is going, so I think you can see how your sentence doesn't work in this situation and therefore shouln't be accepted. We need to learn both 你们 and 大家.