Fieldette, I don't wish to overstep the mark, but please think very carefully before breeding her and look at the number of dogs being killed every year through lack of homes. There is a very real risk your bitch can die through having a litter and/or all the puppies could die too, especially if you are inexperienced in this area.
In order to know if she is really nice enough to breed, she ideally needs to have proven working ability (herself, not her relatives) or be proven in the show ring, which is unlikely for a working bred springer. You won't really know if your bitch is good enough to breed from until she is fully grown.
If you do decide to breed from her then it is responsible to have all the relevent health tests, which are costly and many for Springer Spaniels. Some info on health tests here:
www.sgurr.org.uk/healthnew.php
Many 'breeders do not bother with the health tests and will tell you they are not necessary, this especially tends to happen in working lines, but they are every important, both for the health of any puppies you breed and the welfare of the breed in general. You should also make sure any stud dog you use is properly health tested and no good stud dog owner would agree to mate an untested bitch anyway.
It is also respnsible, if you have a litter, so as not to contribute to the current rescue situation (around 25,000 dogs put to sleep every year) to remain responsible for any puppies you breed for the duration of their life and ask the new owners to return them if they ever can't keep them, no matter what point in their life they are at.