Thats tuff to say, depends on how much its fed, what its fed etc... Reptiles tend to grow the most the first 2 years of their life and slow down from their. I got my one BP around 3 years ago, when I got him, he was only 15-16 inches, he now is about 3ft. You dont want to feed to much though, some people do whats called power feeding, its more common in large boids, they do it to get them to grow faster but its not good for them and will lead to many health problems down the road. Mine gets 1 rat every 7-10 todays normally.
