There is no definitive answer to this question as it will vary depending on a number of factors, including the country in which you live. However, according to the American Society for Aesthetic Plastic Surgery (ASAPS), the average age of patients undergoing breast augmentation surgery in the United States is 34 years old. This age group has been steadily increasing over the past few years, with a significant jump between 2000 and 2010. In 2000, the average age was 29 years old, whereas in 2010 it was 34 years old. The ASAPS data also shows that patients aged 18-24 make up the largest proportion of those undergoing breast augmentation surgery (32%), followed by those aged 25-34 (30%).