Soft Youth

I won't be restating what have already been said. I think both =hefeigal and ~OrangeUtan are stating most of the important things with the model, her pose and the composition, but I'll just add a small comment about the composition. When taking shots like this, try take one with the model to the right and one with the model to the left. It'll often lead to two completely different shots. The background can have a big impact on how the photo looks, and creating several shots with the same model/pose/background but different composition is sometimes a good way to think out of the box.

Now, for the technical parts.
You've done a good job with the editing. It's getting closer to spring (at least here in Denmark) and an editing like this really compliments that! I have to say that the white areas in the background are a bit annoying. They seems a little overexposed, which isn't good.
I don't really know about the background either. It's a good background and it really fits good with the theme and the model, but I find it far too grainy for my liking. This might just be a personal thing, but the graininess is a bit annoying.

Lastly, the models expression is a bit ambiguous, for me at least. I think her eyes looks a bit sad, while the rest of her expression (and pose) tells a story of a happy person. Her expression could have been better, but she's still doing a great job!

All in all, this is a good shot, which reminds me of spring! You're definably capable of taking good shots and the editing is perfect for the theme! There are some minor details, as already pointed out, but these are most likely just because of my liking and not as much your fault