Wow, it looks just like the reference. However, maybe you can intensify the shading a bit more. Since there isn’t a lot of shading in the reference picture, I’d just add more to make it look even better. But it’s up to you. Overall, it looks really good.
The improvement amazed me a lot! The wrinkles are just WOW. The only critique I have for this is to make the shading on the skirt blend in more (turn down the opacity a bit maybe?) And make the back areas of the skirt darker so it can look more like a pleat (folds.) Other than that, everything is very good!