I did not know 6 weeks old is a bad age to pick up a puppy! ?

As I am informed that 6 weeks is a bad age to pick up the puppy. I feel really bad. Its a 3/4 bichon firse and the other quarter cocker. We were supposed to look at the puppy in the showing but the owner kept on trying to make us leave with the puppy and we absolutely loved it. Should I bring back the puppy to their place to live the remaining two weeks with the litter or its too late? I want the interest in the puppy! Should I inform the owner that she was an asshole for selling the dog at a bad age?

Keep the puppy. She obviously wants to get rid of them and doesn't care about them. Instead of informing the owner she is a jerk, make a call to the SPCA and suggest they go undercover and pretend to be buyers so they can trick this woman and fine her.