"A little while ago ... a couple of girls in school made up a video of me and put it up on YouTube," Ali – whose E! reality show, Living Lohan with manager-mom Dina, debuts on Memorial Day – tells PEOPLE exclusively. "They used disgusting words. Like if my mom ever heard me say that stuff, I'd be grounded for life! ... They're disgusting kids. I got really aggravated."
School authorities were notified, the 14-year-old adds, "and [the students] got suspended."
Such problems are a thing of the past, now that the eighth-grader is being home-schooled (to accommodate her work and travel schedule).
"You learn so much more – it's just hard to focus when girls are giving you problems," she says. "No one's talking about you behind your back. It's definitely easier."
She may have a famous sister – and a burgeoning career of her own – but, Ali says, that's not what makes her a target.
"I don't think it's just because of my sister and who she is," she insists. "I think it happens to all the other girls out there, because girls are just mean. It doesn't happen with guys. When I asked [my little brother] Cody, he was like, 'No, Guys don't care!' "