These Mexican sisters give Metallica a run for their money

Dany (15), Paulina (13) and Alejandra (9) have given metal a makeover. The three sisters from Monterrey play guitar, drums and bass respectively. They call their band The Warning, and their covers of Metallica and Ozzy Ozbourne have found a huge audience online.

But how do three preteen girls get into metal? In this case, through their parents. As Dani puts it, "We were listening to Barney and then we'd come home and see—"

Paulina interrupts with a laugh: "Like, Pink Floyd concerts, and we'd be like 'what?' But our parents really gave us this love for music," Dani says.

Balancing school and other commitments with daily rehearsal has been a challenge for the girls. But they say both family and school support them.

In April 2015, the trio appeared on "The Ellen DeGeneres Show," where she announced she'd gotten her sponsor Target to contribute $10,000 for each sister's college fund. That added to the $18,000 raised by their GoFundMe campaign. The girls are using part of it to attend a five-week summer program at the Berklee School of Music in Boston. "Ellen and her team are just amazing," Dani says. "They check on us just to see how we are, how we're doing."

It hasn't always been easy, but Paulina has some words of wisdom for aspiring musicians. "You really have to work hard, but in the end it's always worth it. When you're doing something you love, it's always worth it."