What does minerva mean by she became "free" after moving away to boarding school in the time of the butterflies?

Like many teenage girls, Minerva feels stifled by the rules at home. Her father is strict, and Minerva remembers that "the four of us had to ask permission for everything". In this sense, being allowed to go to boarding school gives Minerva a sense of physical freedom, but the freedom she finds there quickly means much more than being out from her family's watchful eye. It is at boarding school that Minerva experiences her political awakening. Through talking with Sinita, whose family has been decimated by the Trujillo regime, and seeing what happens to a classmate, Lina, who is chosen as a romantic interest by the lecherous dictator, Minerva begins to understand the truth about their "revered" national leader. At boarding school, Minerva learns about freedom "in (her) head". Thinking for herself, weighing the evidence of her eyes and ears, she realizes that she'd "just left a small cage" which was her home, "to go into a bigger one, the size of (her) whole country" (Chapter 2).