Skirts, particularly short skirts worn low on the hips rather than above the hips on the waist look very outdated in my opinion.
It makes it look like schoolgirl's 90s P.E. skirt. Straight non-fitted/non-pleated skirts also look outdated, particularly if it's made of a thick non-flowy material. It looks like a petticoat to me. I think most skirts look trendy when the waistband is showing. As a short person, I don't wear midi skirts as it makes my legs look stumpy. That all said, whether a skirt looks good or not depends on the individual, her body shape/size, and the overall outfit.
At the moment, it seem like everything's "in".