Dry cough, no other symptoms... should be fine?

My little girl is 3 weeks old and has had a dry cough a few days after she was born. But she has literally zero other symptoms. I got a humidifier and it helps a little. But she’ll still cough. I know it’s not the whooping cough from the sound of the cough. And she’ll only cry about it when she first wakes up. Afterwards while she is awake she is a quiet, content little baby. Is there something I’m missing? She has no fever, not runny or stuffy nose. I just feel bad when she first wakes up. Her cough has gotten worse in the past couple of days and she’ll cry about it longer. But again afterwards she is a happy baby. I’m a FTM so this is all new and I want to be sure I’m not missing something bigger with her cough. Thanks I’m advance!