It seems like every other day we read about a major hack or security breach that exposes our personal or financial information.

But last week's news about a data breach at Equifax, one of the three major credit reporting agencies, was different. The type of information accessed -- Social Security numbers, birthdays, addresses -- was particularly extensive, leaving nearly half of all Americans vulnerable to identity theft.

Thieves who get hold of your personal information can open bank accounts, new credit cards or lines of credit in your name -- and destroy your credit in the process.

Identity theft is bad news for everyone, but it's especially dangerous for young adults.

Millennials may need their credit sooner

When you try to open a credit card, or take out a loan to make a big purchase like a house or a car, your credit report gets pulled. It determines whether you get the loan in the first place, and also the interest rates you'll pay. In many cases, your credit history may even be a factor in whether you can rent an apartment or get a job.

While many older adults may already be settled down for the long term in a home or with an employer, people in their 20s might want to hit those milestones in the next five or ten years, said Patrick Amey, a certified financial planner with KHC Wealth Management. Poor credit early in adulthood could make it harder for young people to reach their goals.

Related: Why you need a good credit score and how you're messing it up

Plus, good credit is especially important when refinancing student loans -- a move that could lead to significant savings. If you have poor credit, you may not be able to score lower interest rates on your debt.

... and have shorter credit histories

Decades of good credit can help offset negative hits to your credit score, so people in their 50s and 60s may have an advantage over those in their 20s and 30s.

"[Millennials'] credit history window is so small," said Alexander Rupert, a certified financial planner with Laurel Tree Advisors. So it "will take a long time to pave over those negative marks."

Related: Equifax hack: What's the worst that can happen?

Younger people also have more of their financial lives ahead of them, and could face ramifications from this breach down the line. Matthew Cosgriff, a certified financial planner with BerganKDV, noted that hackers might not use stolen data right away. "This breach may not play out for a really long time," he said. "Impacts may not be felt for years."

What you can do to protect yourself

In order to protect yourself, make sure to check your free credit reports and watch out for outside attempts to check your credit. Those could clue you into whether someone else is trying to open a line of credit in your name. You can also sign up for a credit-monitoring service and put a fraud alert on your credit.

Related: 5 things to do right now if you're worried about the Equifax hack

Cosgriff recommended making monitoring your credit reports and score a habit, "not just now, but well into the future." If hackers sitting on your information use it in the future, you'll know.

Some experts recommend freezing your credit if you think your data has been stolen. That will prevent anyone from accessing your credit report without your permission.