I've put a deposit down on a female Yorkie from a litter of 5 girls and 1 boy. I've gotten 3 different batches of pictures from the breeder. The puppies are only 19 days old right now.
This morning the breeder was asking me if there was a certain puppy that I wanted to claim as mine. I don't feel comfortable making that decision right now and told her I'd like to wait to see them in person. I've been promised first pick, since I put my deposit down first and have been in contact with her since 3 weeks before they were born.
How do I decide?
What should I look for? I tend to be drawn to the darker Yorkies. Is there a way to tell which ones will be darker? With that said, I'm not interested in getting the smallest one, as size won't be a factor in my decision. I really just want it to be healthy and of good temperment. If it were a sure thing, I'd take a purple one if it were healthy, happy and good fit for our family!

I know whichever one we pick, we'll love it.
What age should the puppy be when I make my final decision? I can see them in person weekend after next. (they will be 4 weeks old then)
There's a 1 year health guarantee on the puppies.
Thanks for any tips or pointers you can give me