Definitely a BCI, but since there are so many localities its not easy to tell what type your little boa there is. Some localities are pretty distinct, however more look fairly similar. If the previous owner said its a CA boa I wouldn't put it past him to just assume so. Since there are so many kinds of localities within close geographical proximity from one another in the wild. It is very hard to really tell unless you trace the exact lineage of the animal.

The little guy is definitely under a year old, maybe a 4 months old give or take.

Husbandry is almost the same as BPs though you should play with it a bit to see which is most comfortable for the animal.
As for enclosure size, boas like the extra room to explore and move around. I find them to be much more active than BPs and therefore a good general rule as stated above is at least 1 square foot per foot of snake, but more is always better. Just to be on the safe side a 4x2 AP cage would be the better choice if space isn't an issue. If you snake truly is a female the 4x2 is perfect. A male will probably do fine in a 3x2. It all depends on what you want to do with the enclosure.

Good luck with her!

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