There are many aspects of finding a great pair of fitting pants. Gaping waist, baggy front area near the zipper, nice fit in the butt and of course the length. I think for a short girl it is just as important to have the right leg cut to create a flattering leg. This is even more important with a crop pant. As you can see on this first pair of khaki pants the box crop pant really cuts off the leg, creating an unflattering break and making the leg look shorter.
A more flattering look is this slim cut leg with a rolled cuff or below the straight leg black pants in the last photo. See how they lengthen the look giving the illusion of a longer leg.