At that age mouse fuzzies are too small of a meal. Most ball pythons start out on rat fuzzies and move up from there.
So in this case it's not necessarily terrible advice if that is what you were feeding, it's just the wrong food item. Definitely a bad feeding schedule to recommend.
The right size prey item is very important.
If it were my snake, i would try to move up to a rat fuzzy every 5-7 days for 2-3 weeks. If the baby is taking those well then I would try to move up to the right size. A rat pup is usually the next size. Weanling is after that.
The general target you're looking for is 10% of your snake's body weight. Having a kitchen scale to measure with is a great idea.