(AP) - President Barack Obama went forward with a controversial speech to students nationwide Tuesday, preceding it by advising young people at a suburban Virginia school to "be careful what you post on Facebook."

"Whatever you do," he told them, "it will be pulled up later in your life."

Wakefield High School in suburban Arlington, Va., was the host school for Obama's talk, which has gotten poor reviews in advance from conservative groups and individuals accusing him of stepping too far into local education.

Obama, accompanied by Education Secretary Arne Duncan, met with some 40 students gathered in a school library before giving the speech that was to be carried on the White House Web site to young people restarting school across the country.

"When I was your age," Obama added, "I was a little bit of a goof-off. My main goal was to get on the varsity basketball team and have fun."

The uproar over his speech followed him across the Potomac River, as his motorcade was greeted by a small band of protesters. One carried a sign exclaiming: "Mr. President, stay away from our kids."

Obama told students to "stay focused, find something you're passionate about."

"Whatever you resolve to do, I want you to commit to it," Obama said. "The truth is, being successful is hard. You won't love every subject that you study. You won't click with every teacher that you have."

Obama is not the first president to give such a school-opening talk, but his plans seemed to almost immediately get plunged in controversy. Critics accused him of overstepping his authority, and school districts in some areas decided not to provide their students access to his midday speech.