Hi there,
First I'd like to welcome you to YorkieTalk and so glad you are here!
You are so kind to rescue the sweet little thing from the shelter and giving her a good home.
This is just a thought, but since you might not be aware of Kiki's history, it could be someone was mean to her or kids picked on her while she was sleeping, so she just learned to growl when people bother her.
Possibly as she adjusts to her new surroundings, she might learn to relax a little and calm down.
Anyway....have a wonderful Sunday evening.