Speaking to reporters at Fairfax High School, Danielle Tylim described her ordeal in the Parkland shooting that left 17 of her classmates dead.
"I never would have thought that an 18-year-old would come in and shoot my classmates, and people at my school, and put my school in danger," she said. "But it happened and it will keep happening if we don't do anything."
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She said she was "really lucky" to have been taking a makeup test across campus from where the gunman opened fire.
After a fire alarm sounded, she joined the evacuation of the campus and sent a text message to her mother: "Mom, I don't want you to worry but there's an active shooter at my school."
Carrie Tylim rushed from her family's home to a staging area at a nearby Walmart, where students and staff had gathered.
Tylim said the teenagers were screaming and some were even vomiting as they fled in fear from their school.
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"All I can think about is, 'Not again,'" said Carrie Tylim, whose sons were 4 and 9 years old when they survived a mass shooting at a Jewish community center in Granada Hills.
She added that her sons still deal with the effects of what they witnessed as children. She said they were "right in the lobby where the bullets were shot and saw their campmates hit the ground."
After last week's tragedy in Florida, the mother and daughter traveled to Southern California to be with family members, including Danielle Tylim's grandmother, a Holocaust survivor.
In the aftermath of the school shooting, the teenager said she has been speaking out about the need for reform.
"We're going to keep fighting until there is a change -- we're not going to stop," she said of herself and her classmates, some of whom traveled to Florida's Capitol to meet with lawmakers. "Because this is going to happen again if we don't do anything."