Just over three weeks after a gunman walked into Marjory Stoneman Douglas High School and opened fire with an AR-15 semi-automatic rifle killing 17 students and teachers, Gov. Rick Scott signed into law Friday afternoon a comprehensive school safety bill aimed at preventing future school shootings in Florida.

The National Rifle Association announced shortly after the bill signing that it had filed a federal lawsuit challenging the law. A spokesman told CNN the lawsuit is designed to protect people’s Second Amendment rights.

“This bill punishes law-abiding gun owners for the criminal acts of a deranged individual,” executive director of the NRA Institute for Legislative Action Chris W. Cox said. “Securing our schools and protecting the constitutional rights of Americans are not mutually exclusive.”

Scott and family members of the victims at Parkland defend the law.

“When it comes to preventing future acts of horrific school violence, this is the beginning of the journey,” said Tony Montalto, whose 14-year-old daughter, Gina, was killed in the Parkland shootings. “We have paid a terrible price for this progress. We call on more states to follow Florida’s lead and create meaningful legislation to make all schools safer. This time must be different.”

Montalto and family members of other victims of the shooting attended the bill signing.

For Andy Pollack and his son, Hunter, it was a day of mixed emotions as they watched the governor sign the school safety legislation into law. Pollack’s 18-year-old daughter Meadow was killed at Parkland.

“I wish I could tell you that I’m happy,” Pollack said. “How could we be happy? He buried a sister and I buried a daughter. To me, this is a start for us.”

Within days of the shootings students from Parkland began to organize and speak out about gun violence and school safety. They traveled to Tallahassee to urge Scott and state lawmakers to take action to prevent another tragedy from occurring in Florida.

State leaders heard their cries.

Friday’s bill signing comes exactly two weeks after Scott and legislative leaders proposed separate, but similar, school safety packages.

“As a businessman, I’ve always rejected the idea that government has to be slow,” Scott said. “Today should serve as an example to the entire country that government can and must move fast.”

Scott says while the Marjory Stoneman Douglas High School Public Safety Act isn’t perfect, it meets many of the requirements that he urged legislators to include in a school safety package: increasing law enforcement at schools and hardening facilities, providing more funding for mental health services, providing a mechanism to keep guns out of the hands of individuals with mental health issues, and tightening gun laws.

The debate dominated headlines as lawmakers considered the first gun control measures to be considered in Tallahassee in more than two  decades, which resulted in opposition from gun rights advocates like the NRA.

The school safety legislation raises the minimum age for buying all firearms from 18 to 21 and imposes a three-day waiting period on all gun purchases. It also bans the sale of “bump stocks,” devices that allow a semi-automatic weapon to be converted to an automatic firearm.

The bill  also would allow law enforcement to seize firearms of anyone being held under the state’s Baker Act. Authorities could hold those firearms for up to 24 hours and longer if they obtain a court order.

The school safety plan allocates nearly $200 million to “harden” school facilities and ensure there is at least one school resource officer at every school.

One of the more controversial elements of the plan is a “school marshal” program that would allow certain school personnel who are specially trained and certified by law enforcement to carry concealed weapons on campus to help protect students in the event of an active shooter. Legislative Democrats opposed the measure saying it places more guns in schools.

The original draft of the legislation would have allowed classroom teachers to  participate in the marshal program, but teachers were removed from participating after Scott expressed his objections.

“I still think law enforcement officers should be the ones to protect our schools,” Scott said. “I’ve heard all  the arguments for teachers to be armed and while this bill was significantly changed on this topic, I’m still not persuaded.”

Scott said the fact that the marshal program isn’t mandatory and would be a decision for local school officials, makes the idea more acceptable to him. He says when it came down to making a decision whether to sign the legislation into law or veto it, he asked himself three questions: Will the bill dramatically improve school safety? Will it provide more funding to treat the mentally ill? Will it provide the tools to take away guns from people who shouldn’t have them?

“The answer to all three is–yes,” Scott said. “And that is why I’m signing the legislation today.”

Scott and the families of the Parkland families who attended the bill signing agree the law is just the beginning step in the effort to improve school safety. Both Montalto and Pollack say they intend to work with other states to pass similar school safety measures.

“And after this moment, we’re going to work on moving forward and hitting every other state to make sure they follow the lead of Florida,” Pollack said, “What we did here in Florida is incredible. A bipartisan bill in three weeks. It’s unheard of and we did it.”