how short should I wear it?

Treat it like an essay: long enough to cover the subject, but short enough to keep it interesting

Mid thigh

Keep it classy.

Short enough you have to think before kneeling or sitting.

As short as your courage allows..

about ten inches above the knee

Just above the shoulders

as you like.

Hair or skirt?

Hair or skirt?

your nails?

Not so short that you challenge people in a sexual way. That is disrespectful.