Oh boy. The shot IS underexposed. From the PERSPECTIVE that we are looking at, the focus IS the child, and the childs face isn't exposed properly. Its like 2+2=4 and The sky IS blue. We may have different interpretations on an aethetic level on whether an underexposed shot is cool or not, but that doesn't take away from the fact that it is indeed underexposed.
For me if the intention was to showcase the destruction of the flowers, I would have put my focus close in on the child's hand picking the flowers, maybe try and come from below looking up at the childs handpulling out the flowers so that you can also keep her in the shot and its as if she is reaching down to "pick" us (the viewer).
As for the exposure, popping up the flash would have solved this, not changing the ISO, or increasing the shutter speed. Well no, I would actually increase the shutter speed so that you could get more detail in the background, and dialed down the aperture, so that you aren't getting a nasty wash of light on your daughter (?) and instead a nice pleasing "fill" flash.
As for the subjective quality of the photos - who cares? At this stage with a new camera, the point isn't to take masterpieces, but to get familiar with your new tool. As such, keep on doing exactly what you are doing and taking the exact pictures you are taking.