The composition in this one... mostly isn't. You shouldn't slavishly follow any rules, of course, but here the dead-center composition is boring, and the presence of the flowers would generally mean that you can serve two aims by placing the woman off-center to the right.
She looks like a cardboard cutout. The culprit at this tiny size is not the masking (which may be well or poorly done, can't tell) but the fake shadow, which is completely at odds with the lighting of the environment, and the absence of ambient light from the environment, or its simulation. It looks like a flashed subject who was cut out in Photoshop and plopped into a landscape, then a fake shadow added.
The shadow in the area of her read opens up a whole other can of worms. Perhaps she will feel that you've made her butt look bigger, or perhaps are suggesting that she doesn't have enough junk in the trunk.