That is correct. She is a BCI which is not a "true" red tail. However, they are of the same family. A true red tail is a BCC (BCI = b.c.imperator and BCC = b.c.constrictor). Once you see a true red tail BCC, they are unmistakable. There is nothing wrong with yours being a BCI though. In fact, considering your earlier concerns, you are lucky she is. She'll stay a bit smaller than the average BCC which grow to be veerryy impressive animals and, generally speaking, the BCI's have a nicer temperament.
It's kind of hard to tell from the pics, but she looks to be a common columbian or central american boa constrictor. She's not hypomelanistic or she'd be more pink/peach in overall coloration and she's not an anerythristic either or she'd be more grey and black with none of the rust on her tail. She is normal coloration for a common BCI. That in no way detracts from her beauty! She is very nicely patterned and her coloration is lovely - she'll continue to change as she grows and she'll just get nicer!
Here is a pic of my baby boa. She is also a BCI and she's hypomelanistic...
Thank you so much for that detailed response. Do you think I paid to much for her at $100 dollars? She seems to be in good health and mite free and came from the only reptile specialist in or around the city I live in.
0.1 girl friend(surprisingly awesome about my new hobby)
1.0 boxer/sherped mix brutus
1.0 normal bp yearling named Herbert
0.1 red phase western hognose (worm)
0.1 red tailed boa named Shelby (3 months old)
0.2 annoying cats(my better halves)
couple fish tanks