Read the following excerpt from a personal essay titled "Lost Childhood." What is the main idea of the essay?
Looking back at my childhood 20 years later, I never realized the many opportunities that I received. Back then, I thought my childhood was filled with things that my parents didn't allow me to do. But now, I realize that my parents did allow me to have many positive experiences. I was allowed to travel with friends on school trips. I was allowed to play sports. I was allowed to choose what I wanted to study. When I talk to friends I grew up with, we are amazed by the opportunities we had. We are grateful for our childhood experiences, even though we didn't recognize and appreciate them at the time.
A.
Childhood often isn’t appreciated until we are grown.
B.
Childhood isn’t an easy time period for every person.
C.
Parents often don’t openly express themselves with their children.
D.
Parents often make childhood more difficult for their children.