A. Antibiotics, when needed, can be used at any age. In fact, some newborns are prescribed antibiotics as soon as they are born. So she isn't too young for antibiotics, although that doesn't mean she needed one.
It does sound like she has a simple viral upper respiratory tract infection, which may cause a cough and green runny nose for a week or two. Since it is a virus, antibiotics won't help fight the infection, and your Pediatrician is right that your baby will have to just get over it on her own.
Remember that green mucus doesn't mean that a child has a sinus infection or needs antibiotics. Instead, doctors suspect a sinus infection when a child is sick with a green runny nose for more than 10 to 14 days or if they have a high fever for more than 3-4 days and appear to be ill.
