Skirt in Rome?

I only wear skirts and I too can move the waist down to cover the knees when needed.

As long as knees and shoulders are covered, you are OK -- and this includes males -- for any of the churches or cathedrals. Wear anything you like on the street.

Street wear? As in just walking around? Yes, in fact if you wanted to a mini skirt is acceptable. There’s no real difference between what’s “acceptable” at home and in Italy. Fashion may vary but as far as being acceptable vs offensive, no issues.

The modesty guidelines are only for churches and the vatican museum and in that case if the skirt can be worn in a way that covers the knee and your shirt has sleeves or you wear a scarf on your shoulders inside the church you are fine.

Anything is acceptable street wear in Rome. Go as short as you are comfortable.

What you said would work. Skirts at or above the knee are perfectly acceptable street wear. Knees covered for churches. Italy is one of the few places in Europe that enforces that rule. The rule includes shoulders covered AND the midriff. A bare tummy wouldn't pass either.