Parents face the student loan double whammy

At age 51, Charlene Rose had hoped to be socking away money for retirement by now. But instead, she's still paying off her student loans, largely for a master's degree she got to advance her career. And now she's got three kids in college, each of whom is taking out student loans of their own to pay for higher education.

Together, Rose and her children owe as much as $136,000 in student loans. "I didn't think I would have this much debt," Rose said. But she thinks it's important for her children to get college degrees, even though her student loan debt could affect her ability to retire.

"I think that I'll still be able to pay it off. That's my goal. I just can't see not paying the debt," Rose said. It is ironic since Rose, who lives outside Orlando, Fla., is director of housing for Consumer Debt Counselors, counseling people about their mortgage debt.

Rose is just one of a new group of Americans—parents struggling to pay off student loans even as their children take on new debts to pay for their own schooling. Student loans were once thought of as temporary. But for some Americans, they're becoming a lifetime—or even a multigenerational—burden, as parents become unable to help their children pay for tuition, forcing the children to take on even more debt themselves.

The New York Federal Reserve, which tracks the data, reports that student loan debt is the only form of consumer debt that has grown since the peak of consumer debt in 2008. What's more, the amount owed in student loans is now greater than both auto loans and credit cards, making student loan debt the largest form of consumer debt outside of mortgages. It's all driven by relentless increases in the cost of tuition at a time when the country is struggling with sky high unemployment.

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As a result, student loan debt is growing among an age segment many may not think of as students: Fifty-somethings. Americans 50 to 59 years old owed $112 billion in student loan debt at the end of 2012, according to the New York Fed—up from just $34 billion in 2005. And there are a lot of them. And the average balance per person has increased. Today, they owe an average of $23,820—up from $14,714 in early 2005.

Among Americans 60 and older, student loan debt is growing, too—although some of that may be debt taken on to help children or even grandchildren. Today, Americans 60 and older owe $43 billion in student loans—which is up from just $8 billion in 2005.

Melissa Towell is a credit counselor who helps Rose manage it all. "Thirty percent of my clients are in that bracket of 50 and older, either worrying about paying back their children's loans or paying back their loans," Towell said. "A lot of them just say, 'I'm going to die before I pay this off.'"

Critics say that student loan debt—which, unlike other debts can't be washed away by declaring bankruptcy—has gotten out of hand. "People are still paying off debts that they took out in the '70s," said Robert Applebaum, founder of the website Forgivestudentloandebt.com. "There are also people who are nearing retirement age, but cannot retire because of their own student loan debts."

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But others defend the debts—so long as borrowers are responsible about how much they take on

. "The return on investment for a college education is very high and it is the best way for middle-aged Americans to get a good job," said Molly Corbett of the American Council on Education. "I guess the best advice is to use your head when you are making loans and not to go over your head, to think about the job you're trying to get and whether or not it is going to provide the income that will sustain your family and enable you to repay your loan."

—By CNBC's Eamon Javers. Follow him on Twitter: @eamonjavers