Aww, pretty girl! Congrats!

Costa Rican boas are a locality of the subspecies Bci; it's impossible to be sure of a locality unless you know the lineage, but she certainly looks like a Costa Rican (or at very least some Central American) to me.

If she is Costa Rican (which I think is a safe guess), keep in mind she will grow a bit more slowly and end up a bit smaller than a standard Colombian Bci. My Colombian female was about that size at 6 months, so yours could easily be between 6 and 12 months (though probably closer to 6). But it's difficult to estimate age without knowing locale and feeding regimen.

As far as caging goes, "one square foot per foot of snake" is the minimum, but I prefer a cage twice that size (2 square feet / foot of snake). Boas are nothing like bp's in that they are not content to hide all day. Naturally, ball pythons hide in termite mounds and wait for food to wander by. Boas spend a lot of time in trees and are more active hunters. Both of my boas are very active snakes, and if they feel cramped they develop behavioral issues quickly. Enclosures that are a little snug can be ideal for babies because they provide additional security, but adult boas are rarely nervous snakes, and are going to need a pretty large enclosure. Imo a 4x2x2 is an absolute minimum for any boa up to 6 feet, but for particularly large females I think a 6x2 or 6x3 is a necessity. There are a lot of good cages out there, but I personally love AP's.

Have fun with her! Boas are wonderful snakes, I'm sure it won't take you long to fall in love with them.