DENVER -- A 12-year-old girl is spearheading a campaign to legalize medical marijuana across the whole country.

Alexis Bortell said she and her family had no choice but to move from their Texas home to Colorado to treat her severe epilepsy. Now, her family and a handful of others are suing Attorney General Jeff Sessions and the Drug Enforcement Administration (DEA).

They are demanding "cannabis for the treatment of their illnesses, diseases and medical conditions."

"Ever since I've been on this cannabis, I've actually been seizure-free for – today it's 974 days, so we're coming up on 1,000. So I think that's pretty good," Alexis told CBS News correspondent Barry Petersen.

Pretty good indeed because Alexis had seizures every few days, as seen in videos taken at the direction of her doctors.

Her parents said epilepsy medications didn't work, and there was even talk of brain surgery.

"What do you call epilepsy?" Petersen asked.

"Well, I call it my seizure monster," Alexis said.

But this seems to tame the seizure monster: an oil made from marijuana taken twice a day.

Her family lived in Texas where they couldn't get the oil they needed, but they could in Colorado, where both medical and recreational pot are allowed.

For her father, Dean Bortell, the decision to move here three years ago was an easy one.

"I would die for her. Right? So the least I could do is uproot my life and give her a chance at the exact same freedoms and future I had," Dean said.