My Yorkie boy is 1 year and a little more now. He is pretty much well-behaved but does pull on the leash and walking zig zag when we go out because he is too excited. I wish he can be a little less excited but at 1 year plus he is still a young dog. Training from young and ongoing training is really important to these little guys as I feel that they tend to test your position from time to time. Also agree that nipping should stop to curb it from turning into something bigger when they are older. Mine is being brought to the groomers from time to time just to get them used to groomers. Also trained him to walk on the leash from young although he still pulls
. He loves combing as it will come with massage after combing and I also started it from young. I also brush his teeth and make him wear clothes when it gets too cold. I think you should at least start now and not wait. A firm but gentle training goes a long way.