I say
go for it! If you think that you can handle the responsibility, then why not? I have three children ages 4, 5, and 6, and two dogs (a Yorkie and a pug). I wouldn't hesitate to get another Yorkie (actually Dh and I have been discussing it). Anyways, my Dh works ALOT of overtime, and I take care of everything around the home. Even with 3 young children, I know that I could easily handle a 3rd dog, but everyone is different. As long as you have alot of patience, it can be done.