Yes, it is hard to become a director. There is no single pathway to becoming a director, but typically you will need to have completed tertiary education and have many years of work experience.
It takes about ten years to become a director. At a minimum, you need a bachelor's degree and five to ten years of work experience. The level of education is a major factor in determining how long it will take to become a director.
For example, If you have a bachelor's degree expect to work upwards of ten years, sometimes longer, before being considered for a director position. However, if you have a doctorate degree, you may only have to work for one to three years before being promoted to the same director position.
Overall, most directors of large, publicly listed companies have at least 20 years' experience and a master's of business (MBA) degree. With that said, there are many different types of directors across a multitude of industries, which may require more or less time.