For those who are wondering where the question is coming from -- the OP is a 17 year old African American male who is considering nursing as a career (he started a thread yesterday about men in nursing).
Where I live, in the SF Bay Area, there are many African American nurses, some of whom are also male. Many of our patients and their families are also African American. In the year and a half that I worked in a peds hospital, I never heard of a case of a family requesting a nurse of a specific ethnicity. It did sometimes happen that male patients, or their families, would request male nurses, or female patients would request female nurses. To the extent possible, these preferences were accomodated -- of course it was easy to always assign a female nurse when requested, and not as easy to always assign a male nurse, but when possible it was done.
OP, my advice is, if you want to be a nurse, go for it! You definitely will not be the first African American male nurse in the history of the world, I promise. Good luck with whatever decisions you make about your future career!