Sarah was far from the only student to speak out on Twitter about the shooting, which left more than a dozen people injured. The accused shooter, Nikolas Cruz, 19, has been identified as a former student who was kicked out of the school last year.
"Today I woke up excited to go to school in my cute dress and celebrate Valentine's Day with my friends," a girl named Lyliah wrote. "Today I came home nearly terrified and worried about the people I care about the most. Nobody should have to go through that."
The girl also tweeted that she was scared to hear the names of those killed.
"I cannot stop hearing the sound of the gun as he walked down my hallway," a girl named Morgan Williams wrote. "I cannot unsee my classmates who were shot get carried out by police. I cannot unsee the bodies on the floor. Please keep in mind the horror of what we've gone through today. #prayfordouglas."
Morgan shared a video recorded in her classroom, in which students are heard crying hysterically as police officers remove an injured student from the room. Another student is seen lying motionless in a pool of blood before the person recording the footage flees the classroom and runs from the school building.
“I still can’t comprehend this,” Morgan wrote. “This is my classroom. I’m in this video. I have no words.”
Several students also followed Sarah’s lead in castigating pundits for their comments after the tragedy.
“Can the left let the families grieve for even 24 hours before they push their anti-gun and anti-gunowner agenda?” conservative commentator Tomi Lahren tweeted. “My goodness. This isn’t about a gun, it’s about another lunatic.”
A girl identified as Carly responded.
“I was hiding in a closet for 2 hours,” Carly wrote. “It was about guns. You weren’t there, you don’t know how it felt. Guns give these disgusting people the ability to kill other human beings. This IS about guns, and this is about all the people who had their life abruptly ended because of guns.”
Another girl, identified as Kyra, also fired back.
“A gun has killed 17 of my fellow classmates,” the girl tweeted. “A gun has traumatized my friends. My entire school, traumatized from this tragedy. This could have been prevented.”
She then used an expletive to tell Lahren to shut up.
Students also fought back against YouTube vlogger and conspiracy theorist Mark Dice, who criticized the students who took photos and videos from inside the school as the shooting was ongoing.
“Someone want to tell the Generation Z kids that in the event of a school shooting, they should call 911 instead of posting video of it on Snapchat,” Dice wrote in a tweet that has since been taken down.
A boy identified as Connor spoke up.
“The fact that you think the first thing we did was go to Snapchat is ridiculous,” Connor tweeted. “911 operators don’t need 4,500 calls for the same thing. At least one kid in each room called 911 and the rest talked to their parents.”
Sarah called Dice a “heartless (expletive)” for the tweet.
“And (by the way), as we were running for our lives, we were calling 911 to the point that they told us not to anymore,” she wrote.
The students got some help making their case from celebrities. Actress Shannon Purser, who played Barb in the first season of Netflix's "Stranger Things," backed Sarah up.
“Shame on you, @MarkDice,” Purser wrote. “Have you considered that maybe they wouldn’t want to speak, as it might alert the gunman? That the videos could help identify the shooter and notify others to safely call police?”
Sarah ended her day Wednesday by calling it the worst day of her life.
“I’ve been crying helplessly for hours,” she wrote. “Thank you to everyone for your support. I’m going to try to sleep now.”
As of noon Thursday, Sarah’s Twitter account was restricted to followers only.