Congrats on your baby Bella! I've had our puppy Jaxson for over a month now & he's over 3months old. When we got him he was small under 2lbs but he's now 3lbs & healthy as can be! The vet wanted us to put some weight on him but that was all he said just to free feed like many ladies on here recommended to me when I first got him.
So I say just make sure she is eating & drinking enough. I'm not sure with her being 1yrs old cause mine is still little but i'm sure you'll get plenty of great advice from ladies on this site.