Translation:She fired it perfectly.
I understand the distinction between baH and bach in Klingon, but in English, wouldn't "to shoot a rocket/missile" still be correct?
Yes, the distinction between baH and bach is not made like that in English. However, English has its own rules. One cannot, for example, shoot a torpedo, though one can fire one or launch one, and one cannot launch a gun or a bullet, though one can shoot or fire one.
Whether Duolingo is going to let you follow natural English rules is another matter...