I probably would have done the same thing. Like you said, Penny is
still in the good zone even though it is a little low.
Keep an eye out for any changes in her. A few months is nothing.
My daughter had a parakeet
who was on thyroid meds for
years. Amazing what can be done on any animal to help them
live better lives. Good luck on the next test. Maybe there still
won't be a change. But if she has to go on meds it will be fine.
Carol & Buddy