Small dogs tend to be yappy and hard to train. I'd go for a medium sized dog. A German Shepard need an experienced firm handler. Go to a good shelter that will work to match you with the right dog for your needs. They can help you find a dog with a calm personality to go in an apartment.and who would be easier for a first time dog owner to train. Do consider an older dog that is already potty trained they will be so grateful for being adopted and less likely to chew up your belongings while being trained.