If she was out with the studs for those four or so months she could be anywhere from 7-11 months pregnant...
IMO call another vet and get another opinion. Doing the "wait and see" thing is absolutely asinine.
ETA reread the first post.
Yes she could be 11 months. She could also carry longer, she could also have a false pregnancy or god only knows what else going on. You need to have her checked by a vet.