where did you get the first snake? From a breeder? From a pet store? How old/big was it?
Because I can easily imagine that a lot of the tiny, skinny animals I see at Petco and Petsmart have never eaten in their lives, and would be a challenge for a new owner to even keep alive.
I would wait another month or two, and then buy a yearling with some weight on it. That way it's got a good head start and you know it's eating.
Ball pythons are supposed to be EASY! But I've got a hatchling here that took 2 months to eat. It's no picnic getting an animal like that started. And a lot of what they sell in pet stores in August are hatchlings like that.