Your images both suffer from excessive noise, created by the very high ISO setting you used (12,800). This causes the photo to look out of focus and pixelated. For best images, try to keep the ISO below 800.
You might wish to review the exposure triangle, so that you may understand the relationship of ISO, shutter speed and aperture:
What is the "exposure triangle"?
In your case, you may wish to reshoot, but set the ISO to 400 or 800, open the aperture to its maximum (3.5 hopefully with your lens). Depending on the movement by the child, you may need to keep shutter speed above 1/250th or so. A flash might be helpful.
EDIT: to @mattdm comment: indeed, the image does appear to also be out of focus. If you zoom in, and look carefully, the only item that appears to be nearly in focus is the white bow behind the child. An additional suggestion is to pay careful attention to where the camera is choosing to focus, indicated by the flashing dots in the viewfinder. For the best results, choose single point focus, and put the point on the child's eyes. In 'green' modes on the Canon cameras, the camera often chooses multi-focus, finding several points that are in the same plane. However, this often does not work well with the scene, so the recommendation is for you to choose the focus point, rather than rely on the camera. Look in your manual for how to choose focus points.