The colors and idea on this are excellent. It is an interesting take on the perspective challenge, and is very captivating.
The two biggest things that I can see that would have improved this dramatically is to have at least one of the flowers crystal sharp in focus. That would really give the viewer something to "look" at and base the reflections on. I know photographing with mirrors can be tricky because it seems to "confuse" the camera, so maybe using manual focus (I don't know if you did or not) and nailing the distance that you want ot be focused.
The other thing I think that would have helped the sense of over all balance is to crop it so that the frame coincides with the first outline of the mirror. That would eliminate the black rectangle on the left and might possible make it seem like the viewer is "in there" with the flower. (It might need to be rotated just a bit to do this though.
Some things that might be interesting to play with (I am assuming this looks like you wanted it to, but just in case you didnt' try any of these)--
Put the yellow flower on a blue or purple background to add contrast.
Set the composition on the diagonal running from lower left to upper right instead of through the middle of the frame.
Use a flower that has two colors (yellow center, white petals, etc.)
those are just some ideas if you ever want to try this again.
for me, I would have liked to have seen the foreground flower completely cropped out and cropped in from the left side as well. Perhaps a bit more in focus too. I like the white border and concept - shows creativity.
I love daisies! Great shot. I would have liked it better it the glass or whatever that is behind the daisies wasn't so dirty looking. Please remove the film next time.
oh, believe me I know it's not easy to do this! I have tried the same ideea and then dropped. (well..it was not a flower involved). What a pitty it's out of focus! Anyway, nice colors and composition. You should try this with more dof.