I love it. By looking at it, I can honestly say that this took a long time to finish. The color of her clothes is nicely done, as well. It's the first thing I noticed by a glance.
I love how Luka is easily noticed too although, the red,black and green lines are a bit distracting. Perhaps make it a bit faded. Remember to consider on who or what the viewer is supposed to be focused on. But it's not bad enough that can damage the picture's..elegance.
Her hair is likable but I definitely would consider making the shading a bit darker. For example, a pinkish-purple color would be enough for the hair's shading.
You forgot the shading on her face, or was it supposed to be that way? But it's not too distracting. The rose's shading should be a bit darker as well.
Overall, it's a nice drawing but pay attention to the shading and contrast of the picture. But personally, I love it. Her expression is very, very well done. Keep on improving and I'm sure that if you tried to do this again, it will come out even greater, and more wonderful than it already is.