I would advise wearing what you feel comfortable in. While I really like a lady's skirt a bit shorter than you mentioned--top of the knee or a bit shorter--I don't now how you would like that. The longer length might suit you better, and I really doubt anyone else will much care as long as you don't look garish or tacky.

See this to see what length I am talking about: http://www.glengarryhats.com/skirts/..._mackenzie.php

Long or short will not be commented on negatively.