I am a bit confused about all the talk of whether she was breed or not, and I never could find where you stated the weight, but I think she is definitely old enough to breed, and if it turns out that she was not bred at the previous owners, (you will know after 4 or 5 weeks) I would breed her immediately. I can't really breed her anymore this spring, because after the first of June here in the Midwest it is too hot and humid (at least for my setup). Rabbits that get more than 6 months old or so are harder to get bred, and stand more chances of having problems. After they are about a year old, their pelvis fuses and it is very difficult to use them for does. I have young does saved back that are just getting old enough to breed now. Because of the heat, they will be 8 or 9 months old when they are first bred,and that can be a problem, especially if they don't "take" the first time. If your climate permits it she should be bred as soon as possible.