Oprah says she doesn't see aging as something to lament, but rather as something to celebrate. She points to mentors she admires, many of whom are "celebrating the process of aging with vibrancy and with vigor and grace," including Dr. Maya Angelou, Quincy Jones and Sidney Poitier.
"Maya Angelou is... still doing speaking tours," she says in this clip from "Oprah's Lifeclass." "Quincy Jones... is always off in some far-flung part of the world creating new projects. Sidney Poitier... just epitomizes who and what I want to be if I'm fortunate to live as long as he."
Oprah says we live in a youth-obsessed culture that is constantly trying to tell us that if we're not young and we're not glowing and we're not hot, we don't matter.
"I refuse to let a system or a culture or a distorted view of reality tell me that I don't matter," she says. "I know that only by owning who and what you are can you start to step into the fullness of life. Every year should be teaching us all something something valuable. Whether you get the lesson is really up to you."
"Oprah's Lifeclass" airs on OWN.
Click through the slideshow below to check out some of January's Post 50 Celebrity Birthdays -- including Oprah's!