Six years is much better than 2 or less. That gives plenty of time to find any problems she may have and for her to prove to be the superior dog to be selected for breeding.
As for the question about the stud, that relates to why you are breeding her. You should have some purpose. Do you have homes lined up for the puppies? If you breed him to her, will the puppies be what is needed? There is a wealth of information on breeding at
www.akc.org. It also has information on all the major breeds.