Nia Sims suffers from a rare auto immune disease and is likely to die at a young age.
The Victorian woman was " exhausted but joyous" at Melbourne's Parliament House on Friday when the Assisted Dying Bill passed the lower house after a mammoth overnight debate.
The 43-year-old spent 22-hours in the public gallery at Spring Street watching MPs debate the voluntary euthanasia bill, which eventually passed 47-37.
"I wanted to be part of very historic event that will positively change the lives of thousands of Victorians," Ms Sims told reporters outside parliament on Friday.
"Why I need this law is to give me piece of mind today and every day for the rest of my life whether it be short or long.
"When and if the time comes I will have some control over how long I suffer for, how long I'm starved of oxygen."
Ms Sims said her condition causes all her body tissues to become fibrous and hard and she will eventually suffer organ failure, most likely in the lungs.
She was impressed by the respectful debate but says when it got to dawn, "exhaustion had set in and some people started to unravel".
MPs yawned their way through the final hours, fatigue on every face, as the house battled through 141 amendments, none of which succeeded.
The bill now moves to the upper house for consideration.
Jane Morris, from Dying with Dignity Victoria, who also sat in for the full debate, said she was "very relieved" by the result.
"I have cautious optimism that the arguments that have been put out showing how sound the proposal is will transfer into the upper house," Ms Morris said.
Ms Sims says the message for upper house politicians is that "this is an opportunity that can't be wasted".
"I won't see this opportunity again in my lifetime and I want to see this pass before I die," she said.
Debate is due to begin in the upper house on October 31.
