I have a therapy dog Yorkie too. I agree, early socialization is major important. I take her with me as much as possible and have tried to give her every experience & around people that I can safely give her. Also she is my first dog to take thru obedience training and we did 3 sets of classes of that. It is so much more valuable than I ever knew, and didn't even realize it until further down the road.
Heidi is registered thru our local dog training school's therapy dog group and thru Therapy Dogs, Inc. One thing I've noticed is it often seems most dogs in our group each have some little thing that makes them special & unique that another dog in the group doesn't have. I've found that quite interesting. They seem to have their own giftings & personality that they excel in. I think its kind of neat as people are like that as well.
Of course Heidi, though, she excels in them all!!!!
(I'm just a little partial!) Not really though, sometimes I wish she would connect better with everyone. Some she will connect so great, and the next person she may be like "PASS, let's move on!" Part of her gifting is just looking adorable in her cute outfit & wagon. Brings lots of smiles.