I have to, *have* to address this.
New nurses are ignorant.
So are old nurses who are faced with something they've never dealt with before.
So are medium-aged nurses who have to keep up with new technology.
So are doctors, old and new, rusty and in-practice.
Part of the practice of nursing is scrunching out ignorance: your own and other people's. I would argue that the most important thing that a nurse does is scrunch out that ignorance by giving her* patients the tools and knowledge to deal with their conditions. The second-most important thing she does is squish her own ignorance flat under the weight of her own research, learning, and auto-didact-icism.
Do not ever let your ignorance paralyze you. Hell, if I dwelled every day on how little I actually know about neuroscience, I'd never get out of bed. (Or, at least, I'd have another good excuse for not getting out of bed.) What I do know, I know really well--and I can put it into language that a mentally-deficient turnip could understand. What I don't know I'm not afraid to admit, even to an anxious patient.
Where nursing students excel is in the almost eidetic recall of new stuff a lot of the rest of us have missed. Where they excel is in the energy they put into learning new stuff. They also kick ass at taking a look at The Way Things Have Always Been Done and asking "Why?"
Don't let the fear of your own ignorance paralyze you, whether you're a brand-new nurse, or a brand-new student, or an old-guard nurse trying something new. The absolute worst thing that will happen to you if you show your ignorance is that you'll feel like an idiot for a few minutes. Nobody's going to die. Nobody's even going to get hurt. More than likely, you'll make some pedantic nurse's or doctor's day by giving them the chance to explain something near and dear to them.
I once asked an endocrinologist a fairly simple (I thought) question about something endocriny. He treated me as though I had a much broader base of knowledge on the subject than I actually do and lectured me for three minutes on the ins and outs of that particular problem. (What the original question was has been burnt out of my head by the answer.) Even after he left the English language and started saying "Gleep! Waggado, florischepup mmm nnaaagh wazuuuuu weeeep, *click*!!" I sat there and looked interested and nodded. I learned more than I had in a week that day, even without taking into account the detours I took through Google and dictionaries as I looked up the words he'd used.
I am also now his very favorite nurse. He mostly speaks real human speech to me, even.
That's a good lesson on admitting your ignorance. Remember: if it's too humiliating, you can always get Freixenet Cordon Negro in those itty-bitty bottles for after work.
*Standard disclaimer on using female pronouns to label nurses goes here.