What an awesome shot! The tilt of her head and placement of her hand and the look of the turtle right at her...all come together at just the right moment and you caught it beautifully! Great exposure and composition.
That's exceptionally nice. Two things that strike me favorably are the silhouette-that's-not-a-silhouette (perfectly exposed/processed) and the very odd fact that the lighting makes it look like the girl is IN the tank, underwater, and the turtle is OUT of the tank, floating in space.
The thing I'd change (very minor nit) is to crop just a tad off top and left to get rid of that tiny anomaly of the right rear flupper behind the shell int he upper left corner.
Awesome. I agree, the sihlouete is nice, and the blue background is pleasant. The turtle looks about as good as it gets through a thick piece of glass in my opinion.