Yes. And NO.
If you are infront of a modeling agent, it doesn't matter how short your dress is...if you are short, they know it.. they just subtract the inches from your heels by just looking at you and know. So I would stick to commercial print modeling agencies only. Agencies that accept models of ALL heights. For print, commercials and ad campaigns for commercial products.
Alot of girls think modeling is only "sex sells" and it is not true.
If you have a great smile, energy and girl next door look you should keep your dress a little longer and use your smile!
There are models needed for commercials and ad campaigns and agents want to see that energy on camera and in print.
If you are posing for photos and you want to make your legs look longer then yes inch up the skirt a little higher, and arch your back and point your toes in a natural way that makes your own persona look longer and leaner. You can also ask if the photographer can shoot up at you instead of shooting down at you or at eye level. Sometimes a girl can look taller if she is shot from an angle and up wards. The photographer might have to even lay down or sit! -While you stand up.
Especially forLeg modeling which is also called PARTS modeling. You can Google that.
The short skirt might make you feel like a model, feel hot and attractive and I am sure you are...but if you are petite or shorter than 5'7" then when it comes to modeling your best bet is to be as commercial as possible to get an agent. Alot of shorter girls get trapped into glamour modeling and working with the WRONG people photographers, agencts WHO DON't market them or shoot them in ways they can get ahead.