by 5' I figure you mean 5 inches and not 5 feet right?
5' = 5 foot
5" = 5 inches.
If so, superworms are a no-go until your dragon is at least 16 inches in length.
Waxworms are the equivalent of feeding your children a hersheys bar,
And mealworms are crap to be blunt.
If you want to introduce worms and variety (which you should) you are best buying online. It's cheaper online anyways.
-Brandon