there's nothing wrong with attempting to feed her once a week weather she eats or not, but offering food more than once a week to a non-eater will only stress the snake out.
i'd say a young ball python shedding every 4-6 weeks is completely normal. The faster they grow the more they shed. If it sheds well (all in one or two pieces) then i wouldn't worry at all. if the sheds results in of a bunch of little pieces of skin everywhere increase the humidity