Some people have parents with the money to finance their education after hs, partially or completely, but most have to get grants, scholarships, and loans, besides working pt or ft to pay for it.
Although my mom had the money to pay for college and graduate school, she refused to pay for anything as she informed me it was a waste of money and my time. I ended up finishing under grad and grad, but only because my grandfather (yes the jw one) lent me the money interest free. I continued to pioneer and had a part time job and went to school, but took a break in between my assoc & bach. I look back at it now and think no wonder I feel burnt out at 37! The only thing I was allowed to do was live w/ my mom during my school years because I was pioneering, if I had not been, I have no doubt she would have kicked me out.
And like Blondie said a lot of other non-jws return to school. I have a GF that is 60 and she is finishing getting her BA. She went to school then got a good job w/ the CTA and was there for years and retired when she decided to return to school. She is actually going to the same college as her youngest kid. Needless to say, she is not allowed to acknowledge his presence if she should see him in the halls. Typical kid.