You could probably try something a bit bigger now, if you think your snake is a bit small. Just judge the prey size the same way you would do with a bp. BCI's are a bigger variety of snake than a bp and grow at a faster rate. As long as the prey is the correct size, you're good to go. With all the variety in prey sizes, it becomes hard for any of us to judge which "variety" ( hopper, small, medium, large ) is good for your snake without actually being there and seeing the mouse/rat first hand. I'd say, as long as the prey isnt too big, go for it.