You should feed appropriately sized prey at a normal interval. More frequent feedings with oversized prey will more than likely just make it an obese snake with a shortened life span. They will continue to grow, but at a slower rate as they reach adulthood. One important part of responsible snake ownership is to do what's best for the snake, not what's best for you.
Here's a caresheet http://ball-pythons.net/modules/Sect...warticle&id=59
Many breeders "powerfeed" their snakes, which is pretty much a fancy word for making them obese.
Feed a baby snake an appropriately sized rodent* every 5-7 days; feed an adult snake an appropriately sized rodent* every 7-10 days. They will grow at their own pace. Obese snakes are unhealthy snakes that won't live as long as a properly fed snake.
*An appropriately sized rodent should be the width of the snake at its fattest point; too-large rodents will cause regurgitation, which may lead to regurge syndrome, which often results in a snake that won't keep food down and eventually starves itself to death.
BPs grow the most during their first year of life, although they never stop growing.
The best you can do to ensure that you have a properly-sized, healthy snake is to feed it a normal diet; powerfeeding is unhealthy and inhumane. The largest contributor to size is genetics, which you can't change.