Mirra was 10 months old and had already graduated from obedience school when I got Sydnee. Let me tell you, I have my hands FULL! I don't know if Staffies are less stubborn then
Bull Terriers, but I think you should wait a little longer, but that's just my opinion. There are others here that have had 2 young pups are did just fine with the situation.

I think the decision is totally up to you. Take into account the fact that 2 pups equals twice the vet costs for shots, spaying/neutering, food, collars (because they grow out of them pretty quickly when they're young), 2 crates (if you use them), twice the clean up, ect.