Ohhh for crying out loud this will be the third time I will have responded to this post. I'm getting very frustrated with this upgrade at this point....
At this point everyone has said what I've posted before, but it has been erased with the forum upgrades both times. Thank you for the links Dobe Paws, I had posted the before you breed one both times, at least you got it to stay up! I'll just sum up what I've said....
Prettydobie, are you prepared for the financial end of this endevor you are considering? For one thing do you have a job? You mentioned getting paid to clean your own house, that is not something that will support the money aspect of breeding. And if you or your mom think that you will come out ahead in money by breeding, that is a sad error.
You mention that you will alter all the puppies, honestly why breed and put Trinity through it in the first place? You will have to pay for all the ear crops at a minimum of $200 each, and the alterations on all the puppies at a minimum of $120 each. Not to mention house breaking all the puppies also, as they can't be altered until about 6 months old. And there is so much more to it. The DPCA link Dobe paws gave you gives you an idea of the financial burden you need to be ready to dish out.
In addition are you prepared to health test Trinity? Just for a starters hips, elbows, thyriod, blackdog mentioned much more needed too. If you don't health test her and require the same tests of the sire and there are lurking problems, you are condeming the puppies to a very poor quality of life as the problems will be passed onto them.
The reasons you mentioned to breed are not valid reasons. A doberman is supposed to be a medium size dog, to breed for anything larger is introducing more health problems into a breed that has enough problems already. As for the temperment issue, if all you want is another gentle dog, why don't you go to a shelter or rescue and find a gentle one. They do extensive temperment evauations and will find you what you are looking for.
I'm not trying to be abrupt, but I am very concerned. Just because a dog has an AKC registration, that doesn't make it a singuralty excellant representative of the breed that will better the breed in some way by reproducing, it is just a piece of paper.
Please reconsider and consider spaying Trinity also. It is better for her mental wellbeing and will save you the frustration of dealing with any more heats.