Hi Sastro,
You Grey is still a bit young for breeding. When you choose a female, she needs to be as old or older. At this age, putting a younger female with him would put her health at risk because she would be too young for breeding. Also keep in mind that just because you buy a female is no guarantee they will get along or successfully breed. Parrots are not easy to breed which is why they are so expensive. And beware of anyone selling a “proven” female because this is often a bird who has not been a good breeder for them. Make sure you can take the bird to your own vet before the sale is final.
Thank you for asking Lafeber,
Brenda