For started 6 years old is very much on the old side for a first litter, most good breeders I know would say far too old especially for a dog of that size.
Age aside......
We all think our dogs are one in a million but unfortunately that's not really reason enough to breed. Has she been worked? Shown? Competed in some other sphere? Do you have any kind of external evaluation of her at all? What does she have to offer the breed? There is certainly no shortage of GRs, there were over 7000 registered with the KC last year alone, there will have been countless puppy farm and BYB litters on top of that. Other than being a nice dog is she really exceptional enough to add yet more dogs to those already being bred?
As well as hips and eyes GRs need their elbows scoring and there are also several DNA tests which should be done. Health tests aren't obligatory to register a litter but they are absolutely necessary from an ethical point of view. However they're also not the be all and end all of being a decent breeder.
Are you confident in your ability to objectively evaluate her conformation and pick a stud which would compliment her and hopefully improve upon her weaknesses? Give up on the idea of finding a local stud, it's not impossible but it's unlikely that the best possible match for her (in conformation, temperament, breeding lines, health test results, etc.) will be just down the road. You may well need to travel to find the right stud.
Does her breeder know your plans? Had she placed any endorsements on your bitch when she was registered? Do you have a breeding mentor who would be able to guide you through the process?
Breeding is not risk free, you could potentially lose the bitch, the pups or both. Could you afford an emergency c-section if it was necessary? Normal pet insurance very rarely (if ever) covers breeding expenses.
To be honest the vast majority of that is irrelevant. At six years old your bitch is too old to have her first litter. If you think she's fabulous and want another like her then find a puppy from the same/similar lines.