Congratulations! I'm sure all will go well for you. Just be patient, allow your Yorkie to see and sniff baby when you bring her/him home but NEVER allow them to be alone together just in case. My Misty was fantastic with our youngest daughter when we brought her home. MistyBlue was about 14 yrs old by that time and had been with me all her life. She became very protective of all our daughters but especially the baby
She would sleep under or next to the cradle and would run to me every time my daughter whimpered, snuffled, sneezed, etc
I think Misty thought the baby was hers
All the best to you and your new family.