You're welcome !
By the time pups are between 8 - 12 weeks they have pretty much gained all they can from Mum and litter mates, as in learning how to behave etc, and are ready to be indepenent, so to speak.
8 weeks is very young, if you think about how a pup grows, they literally double in size, from week one to two, week two to three etc, and then comes the walking and talking and learning behaviours. Most dogs are considered pups till they are 12 months and reach 'adolescence' so it's a lot of learning in a relatively short space of time. I suppose one way to view it is that at 8 weeks they are ready to form new attachments, to other dogs and people. If you think about the 'alpha' aspect, I guess between 8 and 12 weeks would be the optimum time to get 'used' to a new owner, and find their place in the world.
If you are thinking of getting a pup, but you feel that the breeder is trying to push the pup onto you, I would give careful consideration. Check out all other aspects of the breeder and other dogs. What's the home like ? Where are all the dogs kept, inside or out ? What temperament and behaviours do all the dogs have ? If you have any doubt at all, DON'T !
You are perfectly entitled to locate a breeder who is happy to wait a little while, to ensure all is well with the pups. Any breeder worth their salt will be more than happy to chat, at length, about any aspect of ownership and their dogs, and to answer as many and any questions you may have.
It's a huge commitment to have a pup, which grows into a dog. You should put as much effort into finding a good breeder of your potential pup, as you do into finding a partner for your children, imo. 