Well, it's not impossible! That's the good news. I began with a rott/lab mix of 8 weeks old and added a 14 week old female rottweiler a couple weeks later. I will tell you that I had help, though. I did not train my dogs alone as they belong to me and my boyfriend together. We took them to classes together - sometimes both pups to a class with one of us assigned to one pup each the entire class so as not to confuse. Sometimes I took one pup to a class on one night and another to a class on another night. That way they received simultaneous training and attended the same classes separately. In the end they both passed the CGC test, but I will tell you that they can still be a handful. It really takes a lot of love and dedication, because they can become excited over birds, other dogs, etc. and not all walks are leisurely as planned. But, I love them infinitely, so I am willing to put up with the challenge prescribed by these strong, intelligent beings. They are part of my family, so-much-so that I recently added a third - the little bugger Betti. And I am unable to walk all three at the same time. I have to either alternate them or my significant other takes charge of either one or two.