I don't think favorite colors have anything to do with it. However, "like a lot of death stuff" is a little concerning. If you mean that interested in the occult or things like that, then that would be contrary to Christian belief.
Golgotha the place where Christ was crucified. Golgotha means the place of the skull. Christianity helps followers lead a life for God and promises a reward for service after death. As one can see life and death play a major part in religion. As for the color black what's wrong with it priest wear it rabies wear it. Black is not a color of evil remember lucifer is the light bringer the morning star.
I love how there was an argument because someone didn't like someone elses opinion, but yes, you can. :) Just because you're Christian doesn't mean you can't wear/like/etc. a certain colour or like certain things. You're good :3
If you are a teenager, that is ok. Have you seen the movie "Harold and Maude"? You MUST see it! He was like that too. Super funny and a classic, favorite movie. Ruth Gordon rocks! . So long as it is just a phase, ok. If you are like that for more than a few years, it is time to check in with a therapist.