I've read everyone's responses and would like to chime in as well. For the most part, I agree with everyone, don't get too hung up with the characters appearance as that doesn't matter in the overall story. (Unless, of course, you written that the character is the only white girl and every other ethnicity discriminates her.) If the color of their skin doesn't affect the plot, then you shouldn't really worry about it. By what you are saying, the people who told you that is no different than movie executives saying having a main character that isn't white (or male) won't sell to movie-goers. Just keep writing what makes you feel comfortable with and disregard criticisms like that and follow what you feel is best for your own story. The thing is they are thinking like marketers and is more concerned with numbers than creative integrity. Also, you shouldn't feel bad about creating a character that is somewhat based off of you. I kind of did that with one of the stories that I'm working on. Now if you end up doing the same thing for other stories you've created, then you may have a problem. You get a pass on that with maybe one or two stories but if you do that with everything that you've created, someone will point that out for you.
This reminds me of when Rockstar decided that GTA San Andreas would have a black protagonist. Because really, it was a new thing at the time, which shows how warped the gaming community was. Strong and independent women came before black protagonists. There was some complaint and even mods that turned CJ into a "white" person. I personally didn't care, I mean, they gave CJ so many fun customization options that in the end it didn't matter whether he was black. (my CJ had blonde patches of hair, though)
Is there a point in describing your MC as white? If its from her POV, how we do even know she's white? Are you going omniscient?
It's nothing wrong here. It's your Novel, you can write it as you want! Why you're thinking about other's opinion? I've also written a similar story in past & sold that in AMAZON; you can also do that very easily. Thanks!
To me it sounds like the real racists are people who somehow find a way to make everything relate back to race. One more book has a white main character and they call it racist. It's true that there are a lot of white protagonists, and in the book I'm writing the main character is black. I didn't decide to make him black to avoid being called a racist, I made him black because it made a lot of sense. This book will be about fighting racial oppression in a fantasy setting, and I thought it would be nice for the main character to have faced discrimination himself.
I once had this advice given to me: Don't do something for the sake of doing it. Let it come naturally. My sci-fi's protagonist is a black woman. Race is not the discussion of my story, it's just how she appeared in my head. It would've been no different if she were an alien with neon green and pink skin. There will always be people who will find something to complain about. Take Naughty Dog's The Last of Us. People actually complained that the front cover of the game had a little girl (Ellie) next to the token grizzled guy and thought she would cause people to not buy the game. They were flat out wrong. It turned out no one gave a damn that Ellie was a girl, that she was on the front cover of the game. They loved the game and it turned out to be one of the best games Naughty Dog had made outside the Uncharted series. So don't worry, no one with rational thought will care. No one cared that Ellie was on the front cover of The Last of Us, no one cared that Aang was white and Korra is black in their respective shows in the Avatar-verse.