Pedestrians pass the bronze Charging Bull sculpture next to Wall Street in the Financial District on October 10, 2013 in New York City. - 

Like it or not, more and more Americans have their futures wrapped up in Wall Street. Old age once included a sizable pension paid for by the employer you retired from. But these days, many Americans have to fend for themselves by saving and investing through 401(k)s and other retirement accounts. That means putting money into the complicated and mysterious gears of Wall Street.

Liz Gross is part of that. The 31-year-old Oconomowoc, Wisconsin resident invests a chunk of her salary in a 401(k). Like many Americans, she thinks of herself as something of a novice when it comes to investing.

“I understand the basic ideas of investing and saving early,” she says. “As far as picking the stocks and the funds that I should be in, it’s not something I’m entirely comfortable with.”

That’s why she chose a target date mutual fund, a popular choice these days. The idea is investors choose the year they want to retire and the fund does the rest. (Ideally, they also check the fund’s fees first.) Each is a little different, but the basic idea is the investments become more conservative over time as the retirement date draws near.

Since so many Americans are investing this way, we thought it’d be interesting to connect Gross with the person managing her future. After we talked to Gross and learned about her investments, we called up Andrew Dierdorf, a portfolio manager at Fidelity. His team oversees nearly $200 billion dollars in retirement money, including the fund Gross has invested in. The futures of millions of American, including Gross, are quite literally in his hands.

We connected them both an invited Gross to ask him questions.

Gross: This is definitely your wheelhouse and not mine, so I kind of wanna turn the tables on you and ask how do you plan for your retirement and have you thought about investing in a target date fund?

Dierdorf: They’re my sole holding in my 401(k) account. So, I struggle with a lot of the same types of issues around making sure that I have my asset allocation appropriate as I’m moving through time. So I’m eating my own cooking.

Follow Mark Garrison at @GarrisonMark