Hi Mary Ann,
I will assume since you state you have no choice it's because the breeder is the only one within your area that you can get the pup of your choice or that you've already paid for this pup.
Many *breeders* (using that word VERY loosely) will sell pups and push to get them on their way early like this. The age of 6-8 weeks is a very impressional time for puppies and it is important to allow them to stay with their moms, even better to stay from 8-12 weeks.
 

eople who are not breeding for the betterment of the breed, showing potential or even to produce a dog that is of superior quality(health testing with certifications) will want the pups gone as early as 6 weeks because it is a lot of work after the mom has weaned the pups and they are not intereted in nurturing and the beginning stages of training young pups.
You may have no choice now but in the future when you are ready for your next companion you will know better on what to look for in a better breeder.
For now, there are plenty of people here who can help you and support your questions. Janet has provided you with a lot of information above. I, along with a few others are breeders and can help answer your questions when you have them.

Please Lord if I must lead only one life, let it be at the end of an Am Staff