The Google boys are growing up. They’re bouncing their adult supervisor.

CEO Eric Schmidt, who twittered “day-to-day adult supervision no longer needed!,” will cede his title to Google co-founder and president of products Larry Page on April 4, the company said in a surprise announcement Thursday. “Larry is ready to lead,” he said.

Schmidt will remain executive chairman, focused, he said, “externally, on the deals, partnerships, customers and broader business relationships, government outreach and technology thought leadership that are increasingly important given Google’s global reach; and internally as an advisor to Larry and Sergey.” Heavy on government apparently, an Eric passion. Presumably he feels slick with regulators.

Eric said it’s an effort to streamline the company’s clumsy three-way management structure and speed up decision making.

In a statement he said “the triumvirate approach has real benefits in terms of shared wisdom, and we will continue to discuss the big decisions among the three of us. But we have also agreed to clarify our individual roles so there’s clear responsibility and accountability at the top of the company.”

There was immediate speculation that the shift is connected to Facebook now being the world’s most visited web site.

Although many people would be glad to see the back of him, Eric suggested he will stick around. The shakeup announcement came within minutes of Google posting handsome fourth-quarter earnings of $8.75 a share versus estimates of $8.09 on revenues of $6.4 billion, up 26%.

Whiplashed, Google’s stock initially didn’t know which way to go. Last we looked it was trading at $637 after-hours, up over the day’s high of $634 and down from a 52-week high of close to $643.