Since it's hard to tell the snakes true size from the photo, I'm going to guess that, being a 3 yr old, it is probably somewhere between 4-5 feet long, and could be housed in a 4' X 2' enclosure. That size will work until the snake reaches 6-7 feet, and then you would need to move up to a 6' X 2' or a 6' X 3' enclosure. It will be easier to tell when you see the actual size of the snake...