There are a few times when you have to be able to prove being a part of a tribe(s) but those are usually tribal issues. Native Americans are the only people in America who have to prove their heritage and I think that is oppressive and racist. I understand that some tribes require absolute proof and that there are some good reasons for that; but I think you should identify as both Native American and Black. Black NDNs are some of the most unrepresented people here; and oddly I notice a lot of people are more willing to accept white passing Natives before Black NDNs. I hope prejudices won’t persuade you to not to identify as native. Wishing you the best. <3