California’s first partner has revealed that she accidentally ran over her older sister in a golf cart more than four decades ago, leaving her feeling “pressure to be perfect” and make the loss up to her parents.

Jennifer Siebel, as she was then known, was a 6-year-old playing with her 8-year-old sister Stacey and other children on the carts during a family vacation to Hawaii in 1981.

Suddenly, the cart Jennifer was in went into reverse, killing Stacey. Jennifer had not seen her older sister hiding out behind the vehicle.

“I felt the pressure to be perfect, to make my parents forget, by being two daughters instead of one,” Jennifer Siebel Newsom told the Los Angeles Times in an interview published Thursday.

“I’m sure there was survivor’s guilt, and I’m sure, in my subconscious, it’s like I have to make up for that loss, and I have to do something to improve other people’s lives or have an impact, double my own, which is a little crazy,” she added. “I don’t use the word ‘crazy.’ But you know, it’s aspirational.”

“I realized that I’m really hard on myself,” Newsom said later in the interview. “I realized that you can’t blame a 6- [or] 7-year-old. You can’t ask them to understand things.”

Siebel Newsom, 48, is the oldest of four surviving daughters and came of age in a conservative family whose patriarch, Ken Siebel was a Republican donor.

An actress and filmmaker, she married Democrat Gavin Newsom in 2008, midway through his tenure as mayor of San Francisco. The couple have four kids of their own.

Stacey’s death isn’t the only hardship Siebel Newsom endured. Last year, she was one of four women who testified against disgraced producer Harvey Weinstein during his California sexual assault trial — becoming visibly repulsed when asked by one of Weinstein’s lawyers to show how she faked an orgasm during a 2005 encounter with the former Miramax head at the Peninsula Hotel in Beverly Hills.

“I thought if I went and spoke my truth that — I didn’t realize how much sexism and misogyny still exists in our culture,” she told the Los Angeles Times about the experience. “I was shocked by that. I was shocked. I really was. I mean, shame on me.” 

“It was a horrific experience. I wouldn’t wish it on anyone,” she added.

Ultimately, a jury in the case deadlocked on the charges pertaining to her allegations against Weinstein.

With her husband rumored to be a future Democratic presidential candidate and due to leave the governor’s office in January 2027, Siebel Newsom told the LA Times her focus is on the Golden State.

“I want California to be that shining light on the hill,” she told the paper. “A place where we’ve achieved equity and women have seats at the tables of power, where there’s no more wage gap, less violence against women, where we’ve institutionalized in government and in the private sector family-friendly workplace policies, recognizing that people have lives outside of work, and where your children are known to have the best start in life.”