i agree with jack. I would breed a young bitch just to ensure she could have pups later on. Nothing worst than finding out a prized bitch is a terrible mother or can't have pups after 5 years of owning her. Breeding her early is not a bad idea.

The knock on using something like frozen semen on a young bitch is you have never seen her welp a live litter.

As far as being rough on the bitch. I imagine it is much easier on a young bitch than it would be on an old bitch who never had pups. Older females who never had a litter seem to have more complications which is why you might want to do one early. I believe it was Ed Faron, who has undoubtedly bred a lot of dogs, told me statistically there was no difference in the number of bad mothers or real complications when it was a young bitch vs a mid aged bitch. Either she is a good mother or she is not and there is only one way to find out... Probably better sooner than later.