Sport bikes are light. If you cant hold one up you shouldnt be riding. Being 4'11" thou, you will probably barely be able to get a foot on the ground. Have you ever ridden before? Seeing that your short, like me, you should start off on something small that you can easily get both feet flat on the ground. That way you can learn the basics of riding, while still having the confidence of being able to get both feet down when you want to. If you start out on a bike where you can only barely get one foot on the ground, its gona take you a long time and many accidents before you finally learn to ride and overcome the initial fear of not being able to touch the ground.
If you already know how to ride and are comfortable on a bike, then as long as you can get one foot to the ground you should have no problem holding up a sport bike. Your really balancing it more then holding it up.