Brittany Maynard, who was recently diagnosed with grade four brain cancer, a glioblastoma, was told she had maybe six months to live. She did not want to wait for her brain tumor to take her life. The final stages of brain cancer are extremely painful and Maynard, who has always been an adventurer, preferred to go out on her terms rather than the way her doctors described a death from brain cancer. That's why she moved to Oregon, one of the five states where terminally ill patients can legally choose to end their lives on their own terms, with the assistance of a doctor.

Maynard is now a volunteer advocate for Compassion & Choices, an organization that strives to legalize physician-assisted suicide for terminally ill people. She shared her heartbreaking story with CNN: just days after she got married in 2013, Maynard began experiencing severe headaches. She was diagnosed with brain cancer on January 1, New Year's Day. At that point, Maynard was told that she likely had 10 years left to live. She scheduled a partial craniotomy to attempt to slow the tumor's growth. However, another MRI in April revealed that the tumor was back, and growing aggressively. Doctors gave her about six months more to live at that point.

With that shortened time frame, doctors also recommended full brain radiation to treat the tumor. Maynard wrote in an op-ed for CNN that the level of radiation they recommended would have destroyed her quality of life, burning off the hair on her head and causing first-degree burns on her scalp. She would likely have experienced a slow death, losing motor function and possibly becoming unable to communicate as the cancer spread. Maynard called this kind of death a "nightmare scenario."

With that knowledge, Maynard decided to make the move with her husband to Oregon state, where she could benefit from the Death With Dignity Act. Legal in Oregon since 1997, a terminally ill patient can receive a prescription that will end his or her life, so that the patient can die on her own terms. Maynard has scheduled her death for November 1, shortly before what would have been her 30th birthday, November 19.

"As of right now, I don't know that I'm going to make it to my 30th birthday, and that's a really difficult thing to process emotionally," Maynard said.

Maynard chose to share her story because she wanted to do something good with her final days, to contribute to a cause she believes in.

"It helps me to feel invested in something of worth, something that matters. Part of what is difficult about becoming so sick is that you lose a lot of your autonomy and your sense of purpose," she said.

Fantasy and science fiction author Terry Pratchett has famously been a big advocate for the right to physician-assisted suicide. Pratchett was diagnosed with Alzheimer's disease in 2008. He was the focus of a 2011 documentary, "Choosing to Die," about the death rights movement.

"I live in hope I can jump before I am pushed," Pratchett said.