Young snakes shed frequently as long as they are growing rapidly. If a snake is not growing rapidly, either because it isn't getting enough to eat, it has internal parasites taking the nutrition and therefore slowing its growth, or simply because it is an adult, then it won't shed as often.

So if your snake is an adult, don't worry at all. If it is a hatchling and growing, it should shed soon. If it is a hatchling and not growing, you need to look in to why it isn't growing.