I agree with most of the posts above re a BC not being a good choice, but you have her now. Borders are bred to be working dogs and as such they are generally gentle and lack the temprement to actually attack a human.
Having said that one BC I had I successfully trained to a high standard in police work. She was phenominal but a rareity and I had to handle her with care when in a crowd.
As for barking, dogs are all different. I have 9 at the moment and one goes hackles up and as noisy as at every strange noise whilst one of the others runs to see what treats she can lick out of the stranger. What you currently have only time will reveal.
Border River Pet Resort