I wouldn't worry too much. It takes them a while to grow that big. My big BCI girl is about 3 years old and she is 6'. If you handle them regularly, they get fairly tame. Rosey the big BCI always likes to come out and sit on me, the couch or the bed. I also leave her cage door when im in the room and she will either sit with her head on the little dam for hours just relaxing or she will curl up next to the open door and sleep for hours on end. But for a female BCI, a good estimate is 8' and like I said, that is going to take awhile, not an overnight thing. Also its not so much the length that gets you as the girth. A male will stay fairly slender where as a female will hit a point where she slows down a lot on length but starts putting on girth. So again, a male will be smaller and thinner where as a female will be longer and have much more girth.