First of all, I adore the use of lighting - the way you've somehow got the foreground darkened and the background blanketed in sunlight is just lovely. I also love the title. The pose of the model is very interesting - I love that they're on their toes, it just looks really happy and quirky.
I do think however a better background could have been chosen. (sorry if that's too bold to say, this is just my opinion.) But I think if you could have found a window that showed a more rural scene you could have really captured the beauty of spring, especially with the way you've shot this. I also would have preferred it if the tulips in the vase were not there - this would allow the background to shine through more and make the foreground slightly less cluttered. I do love the tulip held by the model's side though, so I think if you were to get rid of the tulips on the right it would put more focus on her and create a nicer, almost more personal, impact.
I hope this has helped and I'm really sorry if anything seems too harsh as it was not intended that way. I really like this shot, I think it's very original and I love that you're working with the idea of spring. Great stuff =].
I think that the previous reviewer has totally missed the concept of this image. To remove the vase of tulips would remove the primary purpose of the title. Placing the shot in the urban setting rather than a more rural re-enforces the fact that no matter where you are spring will appear. The model is excited, being fully encased in the sun, up on her toes. Seeing lovely fresh cut tulips, a harbinger of spring, she may even be dancing. The bright sunshine outside the window with the model in shadow, the tulips still in shunshine, is a great use of the light to add to the impact.