
I would agree, if you have a slow maturing bitch (which my bred should be) then it puts that finishing touch to them.
Also they 'grow up', become that self assured adult, without the need to be cocky about it.
Unfortunately with a coated breed you could be waiting at least 6 months, or if the coat comes back soft or wavy, a 12 months to see the best of them.
My two older champion girls have al done some of their best winning as veterans, and both have had three litters, one a total of 18 pups and the other 19.
If you have an overblown young bitch having a litter may make her go over, and become too deep/heavy bodied, but chances are time would have done that anyway.