Picking an older puppy

Question
We were at a reputable breeder today to look at female German shepherd puppies.  The first puppy was 4 and a half mo. old and very beautiful, curious, and friendly.  The other two were 6 wks old with the bigger one being more out going than the little one.  The little one was constantly whining but very cute and friendly.  We loved the 4 mo old but I was wondering if a puppy this old could still be easily trained and also bond with us?  The dog has been in a foster home and the breeder assured us that she has been well socialized.  We also liked the little 6 wk old one that was whining but I'm afraid it could be the runt of the litter or not as intelligent as the bigger pup. Do you think it is wise to take an older puppy like the 4 mo. old?  We're really having trouble trying to pick!

Answer
I would be a little cautious about the 4 month old.  It is a good sign that it is friendly to you.  I would want to take it for a walk and see how it reacts to things such as bicycles, traffic, strange dogs, men, children, and other things it may encounter in its life with you.  With a new litter on hand, the breeder may correctly not want the 4 month exposed to too much.