That model is certainly off to a great start.
Skin color is in what you want it to be. I like my skin for DE warmer, so I avoid the cooler shades. It looks to me like you have a bit of a purplish skin tone for the pictures but they are a bit dark.
One thing that helps is to overexpose you camera settings, to a +1.0 on your exposure settings, if you don't have very bright lights. It makes a difference.
The only thing I can tell you as a new painter is just to practice, you'll get better in time the more you do it.
Off hand I don't see anything wrong with the model as it is.
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