Saving for retirement is one of the most challenging goals facing Americans. Many people don't know the first thing about investing, yet they're thrust into the position of money manager.

Don't fret -- it's not as daunting as you might think. The important thing is to get started, no matter where you are in the scheme of things.

If you're just beginning your career, you have a wonderful opportunity to capitalize on your youth. Don't know the first thing about 401(k) or other company plans? Bankrate's article, "Retirement accounts for newbies," tells you how to get started. If you're not sure how to invest, take some investing shortcuts until you amass a tidy sum.

Once you do that, you can build a portfolio that's appropriate to your age, risk tolerance and goals. After you've accumulated some serious money, you can devise a more elaborate asset allocation strategy that includes a wide variety of different investments.

The ideal time to start is when you're young, even if you're juggling savings and debts, all of which compete for your money.

 The difference 10 years can make
What's the difference if you start your retirement savings at 25 versus waiting until age 35 to begin?

To illustrate, let's imagine savvy Cindy signs up for her 401(k) plan as soon as she starts her new job at age 25. She's able to sock away $3,000 each year for 10 years, and then she gets pregnant and leaves the work force.

Assuming she earns 8 percent a year on her investments, by age 35 she'll have $43,460 saved up in her tax-deferred account. She decides she likes being a stay-at-home mom, so she stays out of the work force for several decades.

Meanwhile, tardy Marty (who likes to party) waits until age 35 to start saving for retirement. So he scrambles and begins saving $4,000 a year (a grand more than Cindy had saved each year). He's the same age as Cindy; in fact they graduated from the same high school together.

Assuming his earnings grow at the same rate as those of Cindy, he'll have $57,946 by the time he's 45. At that age, Cindy's investment will have grown to $93,826.

Marty continues saving $4,000 each year; by the time he reaches age 55, he has $183,048 saved up. Cindy has $202,564, and she still has not added any money to the account since age 35.