In this post, I'm going to tell you why it might not be such a bad thing if you get color mixing wrong.
The first reason is because you can learn from it. When you've mixed a color that isn't what you'd hoped for, don't just say, "Ugh, it's not right", and wipe it up. No, look at it and think, "What could this be good for?"
Just because a color isn't right for what you're painting now, doesn't mixing it can't show you how you could get a good color for something you'll be painting in the future.
I realized this when I was trying to mix a color for this duck's feathers I'm painting. I had a dark grayish purple already and I mixed that into some transparent raw sienna.
This is what I came up with.
This is what I'm trying to paint.
The color was totally wrong for what I was doing, but looking at it, I could tell it could make a good skin tone for some people with darker skin.
The other reason, is something I've said before, and that's color is not that important. Value is. I talked about that more in this post.
So that's why it's not necessary to worry if you mix the wrong color.
Painter of portraits and wildlife