Composition:Love the idea and the combination of the hard lines and angles against the softness and delicacy of the petals and pastels.
Technical:I feel the main let down is the crooked lines due to the lens perspective problems. This can be corrected in PS. The partially greyed background is also an issue...it seems to swallow up the flowers. I feel maybe a lighter background to allow the flowers to control a larger area.
Overall: I feel you are on the right track and I know that next time you will pay a little more attention to the finer detail of the image. Keep up the great work and I look forward to seeing more of your work.