Someone I met last night at a wine tasting made me think of this, but this is how I felt when I was at school. I actually did pretty well at school until around year 12 but was always worried about looking silly when asking about stuff I didn't know. However, people of any age can suffer this partly ridiculous but actually rather debilitating form of fear. (I use the drastic term "debilitating" to reflect the stunted mental growth of one unable to learn.)
The very fear of openly demonstrating a lack of knowledge would lead one to never ask the questions to actually gain the knowledge and subsequently reduce this fear. It is cruelly self-perpetuating. I normally love irony but this endless loop sucks balls.
I'm not sure when I made the transition but after feeling a bit stupid for quite a number of my earlier years, something apparently twigged over a period of time so gradual that I didn't even notice it until later. I started asking questions. I'd apparently shed my fear of looking silly because I liked that it made me look thirsty for knowledge. "He may not know much about what he's asking right now, but if he's so happy to ask questions, then he probably knows quite a bit of stuff generally." That's one perception I fool myself into thinking people have of me. I'm now quite proud to ask about stuff I know nothing about because not only does it make me look thirsty for knowledge, but it makes me look fearless. In a public space others often appreciate that you've asked a question they were afraid to.
The other nifty bonus is that you do actually learn something.
A very good friend of mine pointed out a rewarding moment when travelling. It's the moment after you've asked so many questions from other travellers and gotten so many tips that when asked, you can finally offer your own useful advice to someone else. It's partly egotistical, but damn it does feel good.
Never be afraid to ask questions. Heaven forbid, how else will you know why you shouldn't drink a Pinot Noir from a Riesling glass?