Gov. Rick Scott signed into law sweeping changes to school safety and gun access on Friday — a measure crafted in response to the Marjory Stoneman Douglas High School shooting.

And almost immediately, the National Rifle Association filed a federal lawsuit to block some of it from taking effect.

The new legislation raises the minimum age to buy rifles and shotguns from 18 to 21, which the NRA claims violates the Second Amendment.

The law also extends a three-day waiting period for handgun purchases to include long guns, and bans bump stocks that allow guns to mimic fully automatic fire. It also allows some school staffers to be armed.

The bill balances “our individual rights with need for public safety,” Scott said. “It’s an example to the entire country that government can, and has, moved fast.”

The changes were made in the wake of the Feb. 14 shooting rampage at the Parkland school that left 17 people dead and 17 injured. The shooter, Nikolas Cruz, a 19-year-old who had previously exhibited mental health issues, used a legally purchased semi-automatic rifle in the attack.

Families of the victims watched as Scott signed the measure into law. Andrew Pollack, whose 18-year-old daughter, Meadow, was among the students killed, said he and other parents plan “on moving forward and hitting every other state to make sure they follow the lead of Florida.”

Among the provisions of the new law:

— It allows the arming of school staff who are not exclusively classroom teachers, including librarians, media specialists, coaches and counselors. The program is optional at the discretion of county sheriffs and school district superintendents.

— The measure provides $400 million for mental health and school safety programs.

— It establishes the Marjory Stoneman Douglas High School Public Safety Commission, which will investigate systemic failures in the Parkland school shooting, and develop recommendations.

— It creates a new legal process to take firearms from people who make violent threats to themselves or others.

— It requires every school in Florida to have a threat assessment team to meet monthly.

Most of the law takes effect immediately, although the ban on the sale and possession of bump stocks kicks in on Oct. 1, 2018, to give people who currently own them time to get rid of them.

Scott has disagreed from the beginning on arming school staff and hinted some of the funding for this could be rerouted to hire more school resource officers.

“I still think law enforcement officers should be the ones to protect out schools,” he said.

The armed school staffer program is named for Aaron Feis, the assistant football coach at Stoneman Douglas who was killed in the shooting while protecting students from gunfire.

There is $67 million earmarked for the coming year, but it’s unclear how much will be used. Superintendents at the state’s largest school districts — including all in South Florida — have already said they would not arm teachers.

After the bill’s signing, the first of the session, the families of victims gathered outside the governor’s office. Tony Montalto, whose daughter, Gina, died in the shooting, spoke for all of them.

“We applaud the leaders and members of the Florida Legislature that came together quickly to find common ground, putting aside their differences to move the bill forward,” he said. “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.”

The bill first appeared in the Legislature a week after the shooting, about the same time 100 students from the high school barnstormed through the Capitol demanding change. It was part of a larger movement of gun-control activism by students that will culminate in a march on Washington on March 24.

In Tallahassee, the students cited age restrictions and an assault weapons ban as their top priorities for the legislation. And while the final product includes age limitations, the ban never got in the bill, despite numerous attempts by Democrats. Several polls show that a majority of Floridians support such a ban.

The bill traveled a perilous path to get to the governor, passing the Senate by 20-18 and the House by 67-50. Democrats and Republicans came down on both sides of the legislation.

Some Democrats, especially African-Americans, considered the plan to arm school staff a nonstarter. And some conservative Republicans agreed with the NRA’s view that the bill violates the Second Amendment.

The governor said Friday he and others had to compromise, acknowledging the gun regulations went too far for some and not far enough for others.

“I know the debate on all these issues will continue, and that’s healthy in our democracy. People are passionate in their beliefs and they should be. But, we should not insult or disparage each other. We should work together to make our schools safe for our kids,” he said. “We have a lot of work ahead of us in order to enact these reforms and make our schools safer. This is a time for all of us to come together, roll up our sleeves, and get it done.”