When we did trigonometry at school (year 10), I was ahead of my class (they were doing Pythagoras, which I had been learning for 3 years already because for some reason my year 7, 8 and 9 teachers taught me it when I didn't need it). My teacher asked if I knew how to do trigonometry (which, at that point, I had done about an hour of, about 7 months prior, and that was it) I didn't get a chance to tell her that although my teacher taught it briefly last year, it all went over my head. So, she gave me a year 11 textbook and told me to just work through it. I was too embarrassed to say I was confused, so I just pretended I knew what I was doing for a couple of days until it started to make sense.