In the mid-to late nineteenth century, the United States became the first country to open secondary education to the general public. In the early twenty-first century, secondary education follows a common elementary school experience, typically beginning at age twelve and continuing through age seventeen or eighteen.n the mid-to late nineteenth century, the United States became the first country to open secondary education to the general public. In the early twenty-first century, secondary education follows a common elementary school experience, typically beginning at age twelve and continuing through age seventeen or eighteen.