An 18-year-old says her school turned on her because she chose life over an abortion.

Maddi Runkles isn’t allowed to walk at her graduation from The Heritage Academy in Hagerstown because she’s pregnant. The Christian high school said it’s against their code of conduct.

“A lot of disappointment because I had worked so hard for that, and I made one mistake, and all my hard work was being taken away from me,” Maddi said.

Her son Grayson is due in September. She keeps a sonogram on her bedside table.

But she says her pride and joy is the object of scorn from her school.

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At first, she was suspended for two days and removed from student council, but now 10 days from graduation, she’s not allowed to walk in the ceremony.

Maddi thinks she’s being punished for choosing life.

“But, they won't actually admit that. And I get that, because that would sound horrible. But I mean, all I did that was wrong was just have sex before marriage, which they don't agree with,” she explained.

David Hobbs, principal at Heritage Academy, said it’s not because she chose life.

“The matter is not a pro-life issue. Certainly, we’re pleased that she has chosen to keep her child. The issue is our standard of abstinence,” Hobbs explained.

Anything different would betray the school’s principle: Knowledge forged in faith. On that issue, Hobbs said he answers to a higher authority.

"We are not punishing her for being pregnant; we’re punishing her for a breach of a biblical standard of abstinence,” he said.

Maddi told WUSA9 she considered an abortion early on in her pregnancy.

“But, you know, like, I just couldn't. Because I didn't think it was fair that I should take someone else's life just because I'm afraid of what's going to happen to mine. That's just not fair to me,” she said.

“A fine young lady, yet she made a grievous choice," Principal Hobbs said.

Even after all that's happened, Maddi said she would still walk at graduation, if asked.

“Just to prove that this is how it should be. And for other schools to see, if they have a situation, that you should let the girl walk. It's not fair to take all of her hard work away. Or any guy that's in the situation. It's not fair to take their hard work away, just because they made one mistake,” Maddi said.

And for those who may be in a similar situation, her message is simple.

“For other girls going through this, yeah it's scary. It really is scary. But it really is worth it. Because at the end of the day, you know you made the right decision.”

Maddi said the child's father does not attend Heritage Academy, and they do not plan on getting married.

For now, she's focused on finishing school strong, maintaining that 4.0 GPA, and then she'll take college courses online to stay close to her family.