not really age related, its down to the size of the snake. Bcc and bci grow at different rates and end up hugely different full grown, with bci ranging from 6-9ft and bcc 8-12ft. As a minimum for these snakes allow 1sqft per foot length of snake.
Ahh yeh so if it was a 12foot snake you'd generally recommend maybe a 6 by 2? I was thinking maybe an 8 foot long terrarium with depth being around 3foot and height maybe 3foot too! Would that be okay for a female bci?!?!?
Excellent :) thank you! Also, i've been looking for hides in the past week or two for my boa constrictor and i cant seem to find any that are big enough for her, is there anything you would recommend that i could use as a hide? Thanks