Oh come on, Show me a 12 foot Red tail boa, that WASNT a myth,
lets not exadurate, I have full grown WELL fed, 8-9 foot female Suri's,
they are complete monsters, i have only ever seen TWO bigger then that in my life, (biggest was at 10 and 1/4 foot) and ive heard a few accounts of them getting even bigger, but very few people can PROVE it is,
If you don't have many reptile stores around its probably a Colombian BCI
If its male, it will stay pretty small, 4-5 ft average, female 5-6 Average,
not saying they can't get bigger, with good feeding and care, they may.. but probably not. Nothing compared to some of the BCC Monster locales, so don't worry yourself,
Honestly a RTB is more pleasure to work with then a BP would ever be, Boas are more active, more fun, less picky... if its a boa jump on the offer, BPs are a pain in the ass,