Golden in Heat

Question
We have a golden retriever (champ. bloodlines). She is a little over 2yrs old. We are planning on breeding her with our standard poodle (champ. blood lines). She is on her 8th-9th day in season. She is still fighting him off. She is fine around him in general and will occasionally let him sniff her but everytime he tries to mount she attacdks him. We have tried leaving them alone together in a room and we either hear her growl or walk in to them lying down. Is this normal? Could it be she doesnt want to breed? I have read about 3 books on dog breeding and none of them cover this topic. Do some females just not want to or is their a stage in which they all will. She had a litter of puppies with the previous owners (on her last heat) but the vet said she is healthy and recuperated more than enough the have another litter and then he would suggest either spaying her or waiting a heat or two. Is this normal? It was about 7 mos since her last heat.

Answer
I love dogs and am willing to give hours and hours answering questions from owners that will help the dogs.  I am very concerned about the slaughter of dogs for lack of homes. I am afraid many of the questions here are from poorly informed people breeding dogs.  I can't in good conscience facilitate that.  Go to www.akc.org and read about responsible breeding.  Go to www.petfinder.org and see how many dogs in your area need homes.