Elenafirst off - well done ! There is so much right with this portrait that I want to applaud that first
Now here comes the bits that I think can improve your portrait.
I think her jaw is a bit too square - its a strong jaw but its a little too strong in your drawing.
Also the neck (on the right side of the drawing) needs to be widened at the jaw line - I took some measurements on your reference and it wasn't wide enough in the drawing.
I was going to comment on the right eye but I see in pic 3 that you addressed that - and it is good.
Her mouth is a little fuller than in the reference as well. But hey what's wrong with a little artistic licence there!
While the ear (on the right side again - sorry) can be seen in the photo it is really obvious in the drawing - perhaps if you lost the top of it in the darks of the hair - and blurred it a bit more as well as toning down the whiteness a little.
And the last is her widows peaks are a little high - I think her forehead would look better if you brought it down - a little more on the right than the left.
I hope this doesn't sound too picky because I just love what you have done so far and I could not come close to a portrait like this - I just feel that these things might bring it to where you want.
I am sure that Ernest will jump in and give better feedback than mine - he is so much more talented in this area than me.