In 1993, at the age of 34, I began a Ph.D. at Caltech, which I finished four years later. I probably didn’t make much more money afterward, but I’m a lot more satisfied with my life. Apparently this is a common outcome of late life schooling:
This paper addresses the economic returns on tertiary degrees obtained in ages above 30 for individuals with upper-secondary schooling [in] Sweden [where] labor market legislation supports employees who take a leave to study. … Late degrees were found to increase the employment rate by 18 percentage points and earnings while employed by 12 percent. … The effects were absent in the higher parts of the earnings distribution, and females gained more than men. (more)
Human lives are long. If you are willing to work, you can radically change direction, even at the age of 34.