Flower Girl Anatomy Class?
Besides the obvious clash in art style (realistic for the body, manga for the head which does not work at all), there's some major anatomy problems here. The belly button is way too high up her stomach, her arms appear weirdly drawn (her left arm is crooked in a weird unnatural manner which may be because her elbow is too high up and her right armpit seems to begin about midway at her breast) and her neck looks like it belongs to a man.
Her bra seems oddly drawn, with the bottom of her breast for some reason escaping from the bra (which begs the question, do you know bras work?) with no straps on the side. The angles on the panties are also unrealistically horrible. I really recommend you to take an anatomy class because everything is so twisted. The background somewhat works but feels a bit too simplistic. The colours also make it look like the plants are wilting.
It's not a horrible piece by any means, there are some things that do work, but there's also just so much that could be improved.