you don't need more people to tell you how wrong you are, just a few telling you that it was probably a bad choice and wrong. How wrong is irrelevant really unless you really believe that it wasn't wrong at all.
Minstrel shows are generally regarded as very old-school propaganda. Although it was a form of entertainment, it also served to misinform the public about black people, to make them seem clownish, servile, absurd, sinister. When stuff like that is your only contact with black people, the lies stick, even if they're transparently lies. It introduces a pattern of thinking that confirmation bias will reinforce later. If it's not your only contact, well, it can just be painful to watch.
You're not a racist--your intentions were fine. Almost weirdly admirable. However, this is the sort of thing where you have to appreciate how other people are taking your actions. As soon as that makeup goes on, everything you do will be interpreted as your imitation of a black person, and that can veer into offensive really quickly. Ever heard a comedian do a "white guy voice"?
People generally don't like to see someone transparently pretending to be something they're not, and costumes are generally regarded as mocking. Whether you intend it to or not, having someone copying you is generally not as complimentary in this context.
Black face could be done tastefully and in a non=racist way, yeah, why not. (Theatrical make up is generally for portraying something without actually being that something). There was even a vaudeville performer Bert Williams [link] who did black face and actually was black. That said, there is an unfortunate history of racist satire and stereotyping there, but with very mixed elements as well. [link].
It felt like one of many great ways to beautify myself as I am very narcissistic.
I looked at some examples of black faces done in the past and found that those face paintings were a lot more extreme than how mine looked. I made my skin a luscious copper with gold blush, fine eyeliner, and a mole. I also painted my goatee and mustache black. The event I was at was featuring artwork showing images of Snoop Dogg.
I know now to tread lightly when doing this or avoid it completely. We might as well ban all forms of art because they can all be traced back to a history of racism no?