Very nice. You did soooo many things right in this portrait... I especially like your cool halftones and overall composition. I think that you have a lot of talent and am impressed that you can do so well in a new medium with new subject matter.
There were many years where I was sandwiched between caring for a mom with alzheimer's and my own small children...it wasn't easy. Looking back on that time of my life, I realize how much that experience shaped me in a positive way as the artist I have become. BTW, after she died, the very first portrait I ever painted was of my mother
http://www.kcwells.com/ruth2.htm
Even though you work in isolation, I'd like to think that you will seriously continue to develop your skills. There are posts on this forum about self-study with the Old Masters and I urge you to check them out.