By JULIET WILLIAMSSACRAMENTO, Calif. (AP) â¿¿ Thousands of Californians seeking to buy their own health insurance flooded call centers with questions and overloaded the state's online marketplace Tuesday on the first day of a new federal health care law that will dramatically change the way Americans buy health insurance. Dozens of workers at a call center in the Sacramento suburb of Rancho Cordova began fielding calls after a countdown to the 8 a.m. opening of the health exchange. The agency that runs the exchange, Covered California, said it received 1 million hits on the website during the first 90 minutes after the exchange opened. By 3 p.m., the site had received 5 million hits and the two service centers had received 17,000 phone calls. "We are here in California on the right side of history," Peter Lee, executive director of Covered California, said during a news event in the Rancho Cordova call center, one of three in the state. He said Tuesday was just the starting point, and it was evident that exchange officials had work to do after the website and phone system were hit with a crush of inquiries. While no major glitches were immediately reported, the site was slow to load once users clicked on a tab that said "Start Here." Officials had predicted delays on the first day and said many would merely be seeking information rather than signing up for coverage, which begins in the new year. "Like anything when you first start, you've got to adjust a little bit," said Pat Macht, a spokeswoman for Covered California. "The system's not been down, but it might have had some slower response time. But people are signing up." The agency later said the enrollment section of the website would be down from 9 p.m. Tuesday until early Wednesday to "optimize performance." An agency spokesman, Roy Kennedy, said he did not have details about what work would be done to the site.