In keeping a promise she made to her daughter, a mother is getting very candid about the 20-year-old's heroin overdose death.

Casey Schwartzmier, of Ross Township, Pennsylvania, died Sunday.

"She was funny and full of life and she was a drug addict," Michelle Schwartzmier said.

Michelle Schwartzmier told WPXI that she knew her daughter was addicted to heroin. She said she tried to get her daughter help. Casey Schwartzmier was set to fly out to California the day before she fatally overdosed. She was going to get the help she wanted.

"Her suitcase is still packed. She really was driving hard for this. She meant it," Michelle Schwartzmier said.

Michelle Schwartzmier explained why she thought her daughter did drugs the night before she was scheduled to leave to get treatment.

"She wasn't enjoying this life," she said. "She wanted out of it. She just couldn't figure out how to get out."

Michelle Schwartzmier said the pain of losing her daughter is tough, but she said she had to fulfill one last wish her daughter had.

"She wanted to share her story if anything ever happened to her to maybe help someone else," Michelle Schwartzmier said.

Michelle Schwartzmier said her daughter didn't want how she died to be a mystery and hoped her struggle would help someone else. Schwartzmier kept her promise, writing a very open and honest obituary.

"It was the hardest thing I've ever done in my life. It was so hard. I wanted to honor her memory," she said. "I hope I hit the right words because I feel like Casey was helping me write that."

The obituary describes Casey Schwartzmier as beautiful, strong and a believer in second chances – something her mother said she hopes another mother gets with her child.

"I wish she could have all those things, another chance," Michelle Schwartzmier said.

Casey Schwartzmier's viewing will take place Friday from 1 to 9 p.m. at Lawrence T. Miller Funeral Home funeral home in Pittsburgh. She will be laid to rest on Saturday.

The complete obituary that Michelle Schwartzmier wrote for her daughter can be viewed below:

Casey Marie Schwartzmier, 20, of Ross Township, passed away Sunday, Jan. 15, 2017, accidental heroin overdose after a long brave battle with addiction. She was the daughter of Richard and Michelle (Waldorf) Schwartzmier; sister of Eric Schwartzmier; granddaughter of Mary (Planic) and the late Richard F. Schwartzmier and Jerome B. Waldorf; and also survived by many aunts, uncles and cousins.

Casey never wanted to be defined only by her addiction and mistakes, she was so much more than that. She made it clear if she was to ever pass as a result of it, she wanted people to know the truth with the hope that honesty about her death could help break the stigma about addicts and get people talking about the problem of addiction that is taking away so many young lives. Casey was a beautiful, intelligent child of the suburbs who fell into its grip. It can happen to anyone. She was feisty and outspoken but would do anything for anyone and always lit up the room with her smile and sense of humor, even while struggling with her demons. She loved her family deeply, wanted to adopt every animal she saw and play with every child she came across.

Casey believed strongly in second chances, maybe because she craved another chance for herself and other addicts, so she donated her life saving organs to give someone else, a second chance at life. That was Casey: this amazing woman should be remembered for this and not her mistakes. Casey believed that hiding her cause of death would help no one, but if her story could help just one addict push even harder for another day of sobriety, encourage an active user to choose recovery or shine a light on this horrible epidemic, then it would be worth coming out of the shadows. She was very open about her struggles and now is not the time to change that. This strong attitude with a fierce drive and loving beautiful heart that wanted to help other addicts even in death is one of the many things that she can be defined by, not her addiction.

Casey wanted to live. She had dreams of a future career, children of her own and fought hard all the way until the end, one day away from entering rehab, but couldn't break the chains of this demon that's wiping out a generation. Addiction doesn't discriminate, it will take hold and destroy anyone in its path, including the families and people who love them. Addiction hides in the faces of everyday people all around us. Casey isn't just another statistic or just 'another one gone too soon,' she was a great heart with a bright future and a gift that the world lost and can never be replaced. So the best way to honor Casey, is for people who read this or knew her to think twice before you judge an addict.