Melinda French Gates' father sent her on a work trip at 12 years old. What she learned stayed with her for life.

• Melinda French Gates took her first business course at 12 years old.
• The course emphasized writing and achieving life goals.
• French Gates said she later realized the need to balance goal-setting with enjoying life.

Melinda French Gates picked up her knack for goal-setting at an early age.

During the summer after seventh grade, her father sent a 12-year-old French Gates and her sister off to a business course. It was called the "Successful Life Course," and her dad had attended on an earlier work trip.

He was so inspired by what he learned, she wrote in her memoir "The Next Day: Transitions, Change, and Moving Forward," that he signed his daughters up to attend the class over 100 miles away from her Dallas home.

"'Oh my God,' I remember thinking. 'What did they do to my father?'" she wrote.

Their class used books from self-help guru Dale Carnegie and practiced "mind-controlled relaxation," which French Gates said was essentially power naps. The main lesson, however, was the art of goal-setting. They started with short-term goals and pushed on to life goals — reinforcing their commitment by writing them out each night before.

These are the goals that 12-year-old French Gates set for her future self:

• By age fourteen, to have made the intramural cheerleading squad.
• By twenty, to have taken a trip to Europe.
• And by twenty-one, to own her own car. ("'A Cadillac with velvet seats,' I specified, dreamily," she said.)

After the course ended, French Gates said she kept the navy blue binder she received and continued using it each night.

"Over time, the goals I wrote down started to become more and more serious," she wrote.

Although the goal-setting lessons stayed with her, she added that there was a key part of the class she'd been less disciplined in: reflecting on the goals she managed to achieve. Instead of slowing down after crossing off items on her list, her "entire focus would shift to the next one." Her ambition led her to a job at Microsoft, and, eventually, an estimated net worth of $30.1 billion, according to Forbes.

"I was almost using the goals to just push myself so hard in life," French Gates told CNN's Abby Phillip on Monday.

Yet by 35, she realized it was time to set the goal-setting aside and "ease into life," French Gates said during the live interview. At that age she'd been married to her ex-husband, Microsoft founder Bill Gates, for years and had become a mother. She wasn't done with her ambitions, however.

"I'm gonna have big audacious goals, but I'm gonna give myself some time to achieve them," she said she told herself at the time.