Probally not the worst idea. I didn't actually know kids under 18 were even allowed in. My kids are always wonderful in nice restauants, which we take them to often, but I still wouldn't take the three of them to V&As (and the oldest one is almost 17) or anywhere with prix fixe. Prix fixe does complicate the matter quite a bit, especially when they have adult tastebuds but a child-sized stomach (like my DD13). I just hope that that is the reason why and not because of behavior, I hate when a few bad kids ruin it for everyone. 
