"She was everything I ever could've wanted in a child," Sherman said.
She's still mystified that Seung-Hui Cho, who had a history of bizarre and threatening behavior, so easily bought two handguns, CBS News correspondent Chip Reid reports.
Cho had been declared dangerously mentally ill by a court. Under federal law, Virginia authorities should have sent his name to an FBI database. When the gun stores ran their instant background checks his purchases should have been denied.
In the past year Virginia tightened its laws, sending thousands of names to the FBI, and Congress gave all the states financial incentives to do the same. But progress has been slow, at best.
A year ago there were 166,000 names in the FBI database, today, about 402,000. But an estimated 2.6 million Americans have been declared dangerously mentally ill.
"Eight out of 10 people that have a history of being dangerously mentally ill are still going to be able to buy a gun in this country," said Paul Helmke of the Brady Campaign to Prevent Gun Violence.
Seventeen states have yet to send a single name to the FBI.
Helmke notes that even if Cho's name had been in the system, he still could have bought his weapons at a gun show, where in 35 states no background check is required.
Virginia recently defeated an effort to close the so-called gun show loophole, despite lobbying by parents of Virginia Tech victims.
"If you have someone who's intent on committing criminal acts and they want to get a gun, they're gonna find a way to get a gun," said Morgan Griffith, the majority leader of the Virginia House of Delegates.
Holly Sherman agrees gun control is only part of the answer. The key, she says, is identifying people as disturbed as Cho long before they buy a gun, so that they can't do to other communities, what he did to Virginia Tech.
"Starting tomorrow, I'm going to try to turn around, and try to live again," Sherman said. "No matter where I have to turn to do it, that's what my goal is."
Turning over a new leaf is a goal shared by many at Virginia Tech.