I don't get the whole problem here, some people seem to misunderstand the situation entirely.
You (Greg) were raised in a 'black' culture, and this means that that culture is a part of you and will always be a part of you, regardless of your skin colour. I don't get how people can say: "You're white, start acting white!" - Germans are white, Russians are white, Finns are white and 30% (or whatever) of the rest of the world is white; do they all act the same? There is something fundamentally wrong with the idea that social behaviour is based on the colour of a person's skin!
The culture and social environment you grow up and live in defines who you are, not skin colour. This means that a black boy raised by a Japanese family in Japan will inherit their beliefs and values - you definitely won't see him 'gangsta' rapping his way into and out of every social scene, unless he grows up with others who choose to do the same. It also means that a white kid in New York, whom grows up in a predominantly 'black' culture will integrate - in this case it would even be bad if he didn't! I'm sure it's a lot of fun being white in a black environment and not having any friends, or fitting in at all.
I think that some people seriously misjudge how culture affects social behaviour - the way you act is not programmed into your DNA, it's formed by the social environment and culture, and the younger you are, the less biased you are by the useless crap that racism is, and thus you will integrate normally with whatever social environment you are placed in.
This means that (in my opinion) it's perfectly normally for you to act the way you do, Greg, and although people may say otherwise, it really is who you are, even though it does look strange. :P
It also means that you will still continue to change now that your social environment has changed. If everything goes the way it normally does, you will begin to adopt the slang and style of your current environment, and slowly change - this isn't because you "aren't being yourself" - it's because that's what humans do; we adapt.