"I'm too young to have a child. It's not the right time for me," she said.
She's one of about 700 women in the state who will have the procedure this year - one of the lowest rates in the country.
But for anti-abortion crusader Leslee Unruh, "One abortion is too many."
Unruh is the driving force behind Initiative 11 - a measure that would make abortion a crime, with narrow exceptions for rape, incest or the health of the mother. Her group, Vote Yes for Life, collected 46,000 signatures to put the measure on the November ballot - three times more than they needed.
"[Abortion] is being used for birth control and South Dakotans do not like that," Unruh said.
They haven't been willing to ban it outright. Two years ago, when the state tried to outlaw nearly all abortions with no exceptions for rape or incest, 56 percent voted against it.
But most of those who voted against the last measure would have supported it if it had included the rape and incest exceptions, said Patrick Lalley, managing editor of the Argus Leader in Sioux Falls.
That has abortion rights advocates worried.
They say that if the South Dakota measure passes, it could have a domino effect, fueling efforts to pass abortion bans in other states.
"If this is passed in SD it will have a very significant effect on national politics," Sarah Stoesz, president of Planned Parenthood for Minnesota and the Dakotas said.
Four other states tried to make abortion an issue this fall but only Colorado succeeded, putting an amendment on the ballot that would define a fertilized human egg as a person.
For Unruh, the ultimate goal is to reverse the Supreme Court decision legalizing abortion.
"I believe the Supreme Court judges will see the information we have this time and Roe v. Wade will be over," Unruh said.
Opponents say that view is naïve.
"Leslee Unruh and others have this utopian view that if they ban abortion it will never happen," said Stoesz. "And that's just not true. It will happen; it's just that women will die from it."
Or, as the 18-year-old patient told CBS News, women will just go to a neighboring state where abortion is legal.