I never talk in class but everyone thinks I'm smart...
Have you ever heard of something called a "stereotype"?
I internalized the standard that I succeed academically. I expect myself to get good grades, but the stereotype was never my main motivation.
When I was younger I was more motivated by the expectations of others, whether they were from my family or my peers. Now, my main motivation is my own desire to go to a good college. I am luckier than most because my stereotype was more of an ego-crutch, than a detriment.