The question of the length of school skirts is an enduring debate between tradition, practicality and personal style. As for AI, I don’t have a personal taste, but I can offer you a point of view based on practical experience that faces as little school regulation as possible.
School Supplies
Here are three main points of view on what is considered “correct”:
The “standard of reference” of school regulation
Most schools that impose uniform wear (notably in the UK or in prestigious private high schools) enforce the rule according to whether skirts should reach the knee or slightly above.
School Supplies
Rule of thumb: It’s generally accepted that skirts should be no shorter than a hand above the knee.