
My first question would be what do you hope to achieve by breeding?
If your aim is to found a line to continue long term involvement in your chosen canine hobby, so a puppy that is as good or better than it's mother at the sport your involved in.
The ultimate aim should be to maintain or improve the breed so it can continue into the future for the enrichment of your and others lives.
If the breed is numerically small and needs as many enthusiasts as possible to continue and strengthen the gene pool then even well thought out occasional litters can be of use to the breed if at least some fo the puppies later go on to be included in the gene pool.
As the breed is numerically strong, and especially exploited and popular, then you should really ask yourself would your aims be better achieved by having a puppy from elsewhere (your bitches breeder may be breeding from the mother or sister, or her sire may have offspring being bred from etc), or even a rescue dog.
You say she is fully health tested, so I am assuming at least Hip scored, also elbow scored, with good results, eye tested and has had any other breed specific DNA or clinical tests???
I would then ask myself are her allergies a reason not to breed? Are they common in the breed or line, and how do they manifest.
In some breeds atopy can be serious and debilitating. I am sure you have heard what an awful time and uncomfortable life some Westies have due to the prevalent skin issues the breed has.
A daughter of one of my girls went to a fellow breeder and after her second vaccination at 10 weeks started to have pronounced hayfever type issues, which went on for most of her first year. this caused scarring to one of her eyelids to the extent it had thickened so much that a lice needed to be removed to loosen it.
We decided it would not be a good idea to breed from her and she is now in a non breeding pet home, has grown out of the issue (but will never have the brand of American vaccine she had as a pup). she is the adored companion of her new family and best friends of their little girl who is the same age.