Breeding Schnauzers

Question
What age is too old to breed my mini schnauzer.  she has been kept in wonderful health and she weighs between 14 & 18 pounds.

Answer
It depends on a number of factors.  How old IS she?  If she is in top physical and mental health, has she had litters in the past?

Females are born with all the eggs they are ever going to produce, so the older she is, the less viable eggs she is going to have to work with.

One thing you have to ask yourself is, are you prepared to lose your female?  Breeding and whelping takes a lot out of a female, and in older females there is the risk of complications.