Aquarium or PVC Cage?

[Physician&Snakes]

So, If I'd like to go for one size for it's lifetime, a female could be better? Because I was wanting a female already. Though if needed, I might get tubs for a while.

3ft long X 18in-2ft wide is a good size for most specimens, including females. If you want to go ahead and use the adult cage that is fine, but most would prefer it if you placed a divider in the middle giving a young specimen a slightly smaller space, which promotes security.