Do a diagnosis of acute pneumonia require hospitalization to a otherwise healthy 43 year old female?

Not necessarily. If your pulse isn't too high, and you can drink fluids, and followup can be obtained, and you don't have chronic immune system issues, then acute pneumonia can often be treated successfullyas an outpatient.
Hospitalization? There are criteria to help doctors to decide if hospitalization is necessary. Many time in this situation hospitalization will not be necessary. Vital signs (called vital for a reason), pulse, how fast respirations are, blood pressure, some lab values, degree of xray involvement and a general impression of how sick someone is will assist a doctor to decide if hospitalization will be necessary.