Why do people who are exceptions to stereotypes of their race think they took down the stereotype altogether?

Well i i think its because they feel angry because of the fact they have broken a stereotype themselves but yet its still there. i myself am black and i go to university, never done a crime in my life and have several brothers and cousins who are engineers or doctors, however i still sometimes feel ashamed of being black because of the stereotypes. You see stereotypes are not just some belief that is out there, for me its also a reason not to do anything stupid b/c ppl will think its becuase im black. and a reason not to go near a police officer or talk to him, other wise people will think i have committed a crime. Its also a reason i cant joke to my friends about getting bad marks otherwise they will think because im black. i don't dont feel like i have broken a stereotype, i probably believe its still true but it really effects my life in a negative way.