This is a very beautiful painting. You have talent and a great imagination.
I'd like to start this critique off with a few positives. The first thing that pops up is the beautiful scenery. The cherry blossom to the right creates a beautiful frame, along with the tree and bushes. The girl's expression, to me, brings a feeling of longing for something or someone that has gone or out of reach. She seems lost and confused, far from her dreams. This feeling goes very well with the scenery, which is beautiful and peaceful...a place where she can really think about things and hope for the better.
Now, I would like to talk about some things that may need improvement, though there aren't many. The big thing is the grass to the right of the picture. It seems very still, and it looks like just about every blade of grass is going in the same direction. It doesn't seem as realistic as the grass to the left. It takes the individuality away from each blade and makes it seem as if it's just one big thing with a bunch of lines. Another thing is that the flowers on the cherry blossom may need a tad bit more detail, though too much detail would take away from the main point of the painting, which is the girl. And lastly, I think that the girl's eyes are just a bit too far apart. It may be the style, or it may just be me...but I think having them just a bit closer would make her look more normal.
I know that may seem like a lot in need of fixing when you first look at it, but they're really small problems. Some may not even need much fixing at all.
And now I'd like to point out some parts of this piece that really makes it special. One thing is the pedals floating all around. I believe that they make the picture seem more real, not only giving it a sign of wind being present, but they also create a feeling as if memories are either slipping away or coming back, as if they're blowing in the wind like the pedals. I also love the way you made the sunlight show through the tree a bit, and I even see a couple of sun rays in front of the tree trunk. Very realistic. And the dirt under the grass is a brilliant idea. Not many artists do that, but it really does make it that much better. The colors of the tree trunk and the details of the bushes are also very good....as well as the details on the girl's kimono.
And on top of your great ideas, you are very good at shading and highlighting too!
Great job, and I hope that this critique has helped you in some way.