I am in my 50s and am making twice the average salary in my discipline as a DBA. My goal this year is to move to triple.
Going to school will give you a piece of paper. So will getting a certification. No big deal. Rote memorization of the answers without comprhension of why the answers are correct will get you a piece of paper.
You need to ask yourself two questions:
If you are not working on improving your skills, knowledge, expanding your experience every day; then you will be a low end guy no matter what paper you have. The paper may be a key to enter a new career, but what you can do when you enter the door sets your salary.
Education is a life long process, not milestone.
If you are in your thirties and have not discovered how to teach yourself anything you need to learn, then all the schooling you have taken to date is a waste of your time, as well as any future schooling. You will always be surrounded by people making more than you doing the interesting work.
Never ask two questions in a business letter. The reply will discuss the one you are least interested, and say nothing about the other.