Is it safe to take my newborn out in public? She's so little.

Being outside can be great at this age if she does not get too hot, too cold, or too much sun exposure.

The concern with being around other people is catching infections, which you prefer for her not to do, especially in the first month. Most of these would be caught from handling, so you might want to minimize the number of people who hold her and have them wash their hands first. You might also want to avoid staying for a long time in enclosed spaces with poor circulation where people are coughing or sneezing.