When Carla Harris's high school guidance counselor told her that she shouldn't waste her time applying to three Ivy League schools, she did it anyway.
It was a good thing she didn't listen. Harris got into all three schools and a few years later graduated magna cum laude from Harvard University.
Similarly, when her peers told her she should stay away from Morgan Stanley's mergers and acquisitions division because it was too demanding, she ignored their advice and went for it.
Today, Harris is a vice chairman at Morgan Stanley and one of Wall Street's most influential women.
When CNBC asked what advice she'd give to her 20-year-old self, she said confidence is key to getting ahead in life.