The young woman at the center of a landmark lawsuit against Meta testified Thursday in Los Angeles Superior Court that her addiction to social media began when she was just 6 years old — a habit she said consumed her childhood, derailed friendships and spiraled into depression.

“I just felt like I wanted to be on it all the time,” the 20-year-old plaintiff known in court papers as “K.G.M.” said in court on Thursday.

“If I wasn’t on it, I was going to miss out on something.”

K.G.M.’s testimony came as the California Post reported that Meta tried to block her attorneys from asking CEO Mark Zuckerberg about his massive fortune.

Zuckerberg last week was grilled over whether his company designed its online platforms to hook users, though he defended features such as Instagram’s beauty filter.

K.G.M., the Chico, Calif. resident, testified on Thursday that Meta property Instagram “made me give up a lot — my hobbies and old interests,” describing how constant scrolling isolated her at school and warped her self-image.

“It prevented me from making friends because I was on my phone at school. It caused me to compare myself to other people and that made me feel very depressed,” K.G.M. testified.

The case brought by K.G.M. is a closely watched bellwether — one of thousands accusing social media platforms of deliberately designing addictive products for children.

The company has denied the allegations, arguing it works to protect young users while preserving “freedom of expression.”

The day before she took the stand, jurors heard from one of the young woman’s former therapists, who testified about her mental health struggles during adolescence.

Victoria Burke told the court that the plaintiff was diagnosed in 2019 with social phobia and body dysmorphic disorder after reporting distress over her appearance and social interactions.

Burke said the young woman often used Instagram as an escape from anxiety-inducing situations at school.

Burke testified that social media addiction could have contributed to her diagnoses, though she stopped short of saying it was the sole cause.

She also recalled that a vice principal at the plaintiff’s school recommended she delete her social media accounts because she was being bullied.

The testimony came as lawyers for Meta and YouTube have argued that turmoil at home — not Instagram — drove her mental health issues, seeking to cast doubt on whether the platforms were responsible for her struggles.

During opening statements, Meta’s attorney told jurors that the plaintiff’s medical records reflect a troubled upbringing, including allegations of verbal and physical abuse and a strained relationship with her parents, who split when she was 3 years old.

Her mother is expected to testify after her daughter finishes on the stand.

Her own legal team, however, has cited internal Meta research suggesting that teenagers facing instability at home were more likely to report habitual or unintended use of Instagram.

Plaintiff’s lawyers argue that core design features — including autoplay videos and an infinite scrolling feed — were intentionally built to maximize engagement, even as concerns mounted about the mental health impact on young users.

They contend that “like” buttons fed adolescents’ desire for validation, while beauty filters distorted their sense of self.

Attorneys for YouTube countered that the plaintiff did not take advantage of safeguards intended to curb harassment, such as comment controls and screen-time management tools, according to court filings.

YouTube’s lawyer also pointed to usage data showing that, on average, she spent roughly one minute and 14 seconds per day watching YouTube Shorts and about 29 minutes per day streaming videos over the past five years.