I am currently housing my 3 month old ball python in a plastic tub and will continue to do so for a while and today my friend gave me a free tank it is 31" x 11" and the glass at the front curves out about another 2" in the centre.

my question is how big will my ball python have to be before it can be moved into it and how big will it be before i have to move it out into a bigger tank?

thanks for the help!