I think it is ok to be quiet. Just don't let being quiet keep you from stepping up and volunteering for learning opportunities. If you stand quietly behind all of the other students your instructors will likely conclude you are trying not to be noticed because you lack the confidence. It might not be an accurate assessment, but how is your instructor to know if you don't step out of your comfort zone? As nurses, we have to do that sometimes. And by all means, ask questions. Be brave and answer a peers question if you know the answer. I think your instructor wants to know that you can advocate for your patients and for yourself. Sometimes, being an advocate means being loud until someone listens - loud, but not obnoxious.