Too many millennials (ages 23 to 38) are in the dark when it comes to their savings. Nearly half (48%) don't know how much they have in their personal savings, according to data from Northwestern Mutual's 2019 Planning & Progress Study, which polled more than 2,000 U.S. adults.

It's important to be aware of how much you're saving so you know if you're on track for a comfortable retirement or to reach your other financial goals, such as buying a home.

"As you age, the importance of understanding your personal finances continues to make a larger and larger impact," Emily Holbrook, senior director of planning at Northwestern Mutual, tells CNBC Make It. "You have less time to recover from any losses or mistakes that you might make."

How much should young people have in the bank? There's a lot of room for debate, but Fidelity, the nation's largest retirement-plan provider, provides some goals to aim for:

By 30: Have the equivalent of your annual salary saved

saved By 35: Have the equivalent of twice your annual salary saved

saved By 40: Have the equivalent of three times your annual salary saved

In addition to retirement savings, experts also recommend saving up an emergency fund of three to six months' worth of living expenses.

For many people, this advice can be overwhelming. But it's key to remember that what's important is getting started at all. As a first step, Holbrook recommends that millennials leverage the resources available to them. "If they're established in the workplace, really making sure that they have a firm understanding of their 401(k) plan," she says.

Remember, if you're in your 20s or 30s, you still have decades to save for retirement. "The younger you are, the more time you have to make up for lost time," Meghan Murphy, a VP at Fidelity, previously told CNBC Make It.