America's younger generations face a bevy of problems, including mounting debt, impending problems with Social Security and Medicare, and the prospects of an economy that no longer promises advancement over their parents' standards of living. In response, many 25- to 40-year-olds no longer expect to be able to stop working -- no matter how old they get.

A new study from Scottrade and BetterInvesting shows that more than two-thirds of Generation X investors don't believe they'll be able to afford to retire. Although they know that they need to save up a substantial nest egg to quit working -- 37% want to save between $1 million and $5 million -- many in this age group haven't yet dug themselves out of debt, let alone started to save toward long-term goals like retirement.

The most to gain
When you're facing student loans, a challenging job market, and uncertain prospects for the future, it's easy to let pessimism take over. With such monumental challenges, young adults can feel powerless and out of control.

But young people have one powerful ally on their side: time. Whereas those who show up late to the retirement savings game have an uphill struggle, it takes so much less to save up a sizable sum as long as you get an early start.

For instance, if you're 25 and thinking about starting a savings program, you might find it difficult to scrape together even $85 each month. Yet if you save that $85 diligently month after month and earn 12% on your money, that'll add up to more than $1 million at age 65. And that's assuming you never once increase that $85 amount in the future.

Starting good habits
No matter how little you're able to save, getting in the saving habit is a smart thing for young adults to do. As you earn raises and find better financial prospects, your saving habit will grow, allowing you to take even longer strides toward financial independence.

Still, it starts with baby steps -- and the problem is that those steps look so small that you may not even think it's worth trying. But it can make a huge difference. Just a few thousand dollars after a year or two will form the backbone of your long-term nest egg. It can make or break your financial success.

How to start
When you have time on your side, you can afford to be aggressive. An exchange-traded fund like PowerShares Dynamic Aggressive Growth (AMEX: PGZ), for instance, focuses on high-growth companies like Fastenal (Nasdaq: FAST), (Nasdaq: PCLN), and MasterCard (NYSE: MA).

Similarly, plenty of mutual funds seek out high-growth prospects. The Bridgeway Large-Cap Growth Fund (BRLGX), for example, has benefited from great results in companies like Intuitive Surgical (Nasdaq: ISRG), Monsanto (NYSE: MON), and Gilead Sciences (Nasdaq: GILD). With three-year average annual returns of more than 10% in a tough environment, Bridgeway would have gotten a young person off to a strong start.

No matter how you decide to invest, don't let gloomy forecasts stop you from making plans for a bright future for yourself. You have everything you need to take control of your own financial destiny. All it takes is the determination to stand up and fight for your future. If you work hard now, you won't have to work forever.

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Fool contributor Dan Caplinger isn't planning on working forever. He doesn't own shares of the companies discussed in this article. is a Motley Fool Stock Advisor recommendation, Intuitive Surgical is a Rule Breakers pick, and Bridgeway Large-Cap Growth is a Champion Funds selection. The Fool's disclosure policy never quits on you.