Susan Wojcicki, the chief executive of YouTube, will step down after nearly a decade in the role. 

“Twenty-five years ago, I made the decision to join a couple of Stanford graduate students who were building a new search engine,” Wojcicki wrote in a post published Thursday. “Their names were Larry and Sergey. I saw the potential of what they were building, which was incredibly exciting, and although the company had only a few users and no revenue, I decided to join the team.”

Wojcicki wrote in the post that she plans to focus on her family, health and personal projects. She will keep an advisory role at Google and Alphabet, which owns YouTube. 

She also thanked Page and Brin for inviting her on what she says has been “the adventure of a lifetime, calling it a dream “working for a company with a mission that could change the world for the better.”

Wojcicki had a close relationship with Brin, as her sister Anne Wojcicki, co-founder of 23andMe, married the Google co-founder in 2007. The couple divorced eight years later.

Neal Mohan, chief product officer at YouTube, will become the new head of YouTube, Wojcicki wrote in the blog post.

Mohan came to Google through the DoubleClick acquisition in 2007. His role grew to become senior vice president of display and video ads, and then YouTube’s chief product officer in 2015.

He set up product and UX teams, played key roles in the launch of some of the biggest products including YouTube TV, YouTube Music and Premium and Shorts, and led the Trust and Safety team, developed to ensure that YouTube lives up to its responsibility as a global platform, according to Wojcicki.