I'm ditto Zap. I have a hard time feeling psychologically comfortable in a knit skirt in a more formal business setting. Sometimes our clothes are armor, especially us lawyers. Knit skirts in more formal lawyering settings just feel too casual, too soft. In light of where you plan to wear it, I think you might hold on to it, but hold off wearing until you are sure it will work for you. Your pencil skirts and that Theory suit and HL jacket will all be great workhorses for you.
BTW, love the short plaid skirt. What do yo think about its functionality? When it is warm enough to wear without tights or hose, are you going to reach for your booties? Or will the warmth tempt you to sandals? Or are you a non-sandal wearer? I have the vague memory that you may have said sandals are not a very useful option for you, but booties are. In which case, you are set!