Now her mother is her teacher, and said she agreed to pull Black out of school because her daughter was being made fun of and so she had more time to focus on her career.
"She certainly did not need that kind of pressure," Marquez said.
But online, Black continued to be a target. In May, CNN.com's iReport, an online service where viewers can submit stories and tips to CNN's website, had a story posted claiming the then 13-year-old was pregnant, complete with a fake photo-shopped picture of the pop star holding a sign announcing the pregnancy.
"Waking up to a rumor that you're pregnant is not fun," Black said. "It's just frustrating, because I mean, I'm still, like, excited over my first kiss."
Black responded to the allegation on her Twitter account, saying "I thought it was May 15th...not April Fools Day. I'm absolutely NOT pregnant." The story was eventually taken down from iReport.
But the comments became even more violent and alarming. Her mother said the FBI became involved when her daughter began receiving death threats.
"There's not a stone that's left unturned when it comes to her safety," Marquez said. Despite facing so much scrutiny so young and so fast, the teenager seemed to have a remarkably thick skin.
"I've had a lot of experience with not being likes and all that," she said. "I think if I hadn't had to deal with that in the past then I totally would have handled this differently and I would have gone down in burning flames. But I've learned that you just can't let it get to you."
And now it's Black who has the last laugh -- even pop icon Lady Gaga says she is a fan.
"I say Rebecca Black is a genius, and anyone that says she is cheesy is full of s---," she said during the Musicians@Google event this past March.
Now Black says she can't go anywhere without fans flocking around her, and she now has her own entourage: a publicist, a manager, a stylist, a make-up artist and sometimes a bodyguard. A growing fan base also means a growing bank account. Black said she didn't know how much money she has made, but she admitted it was enough to pay for her college tuition.
Working to keep her fame alive, Black just released her new single, "My Moment." Her new music video was an elaborate production -- with nearly 100 people working on set.
"My Moment" already has nearly 22 million views on YouTube -- but with double the "dislikes" from viewers. Either way it's more fame and more money for Black, who says her latest song is much more personal.
"The first line is, 'Weren't you the one who said that I would be nothing,' which is basically saying that to everyone out there that has said that," she said. "The next line is, 'And now I'm about to prove you wrong,' because I am. I will be able to prove all of these people wrong. I am worth something and I will be big."
Watch the full interview on "Primetime Nightline: Celebrity Secrets'" special "Underage and Famous," airing on Wednesday, Aug. 10 at 10/9c on ABC.