The best piece of advice that I received while in business school at USC was this:

Take your biggest risks while you're young.

Why? Because:

You have nothing (or little) to lose.

As you get older, you acquire more and more responsibilities (marriage, children, house, bills) that make it harder to take big risks. Take your biggest risks now while your life is relatively lightweight.

You are flexible and resilient.

You are young. You're basically a super elastic rubber band that hasn't lost its stretch. You can probably take a lot (more than you think) and bounce back in no time.

You want to fail sooner than later.

You hear tons of entrepreneurs say to fail fast or fail forward. That's because failing is a sure way to learn—failing shows you one way that won't work; now you've crossed one off the list and are that much closer to success.

Now is the best time. 

If you dream of achieving something, then you may as well start investing in it as early as you can.

In the end, it's up to you to weigh the costs and benefits and decide how big of a risk you are willing to take. But how will you know if you don't try?