Bill Cosby is waking up behind bars in a Pennsylvania state prison. A judge sentenced the 81-year-old to three to 10 years in prison Tuesday for drugging and sexually assaulting Andrea Constand at his home nearly 15 years ago.

More than 60 women have accused Cosby of sexually assaulting them. The man once known as "America's dad" will have to register as a sex offender for the rest of his life. Legal experts tell CBS News Cosby will likely be in prison at least a year before he sees any action on an appeal. Cosby's spokesperson, Andrew Wyatt, says his client will appeal.

CBS News' Jericka Duncan spoke with one of the prosecutors, Kristen Feden, in the case that started 33 months ago. Feden traveled to Toronto three years ago to interview Constand when the district attorney was considering re-opening the case. Early on in the investigation, she pressed the district attorney's office to charge Cosby and if not for her, the DA said his team would not have gotten the conviction. She is now a lawyer with Stradley Ronon.

"It was very touching," Feden said of that credit from her superior. "It meant a lot to me because I have two young boys, I have a wonderful husband, I have a wonderful family but I put in a lot of sacrifice as well for this case….and with all of my sex cases, I don't recommend charges lightly because I understand the stigma that can attach when someone is charged with a crime as serious as sexual assault."

Feden pressed for those charges against Cosby back in 2015, before the Me Too movement put a spotlight on sexual misconduct.

"I think that the Me Too movement is a very powerful movement because when you have a victim of crime, and I think it's important to just go back to victims of crime, they're humiliated, they're ashamed, they're embarrassed....That isolation, that feeling that they won't be believed and unfortunately you saw it with Andrea Constand. You see it with the Kavanaugh accusers," Feden said.

After Cosby's sentence was handed down, Feden said she asked Constand if she was happy with the outcome. "And she said 'yes.' And that meant the world to me," Feden said.

"I believe that I was part of a very important case and I had a team of people to help me. I had, as I have in many cases, a very strong and courageous victim."