Festivities included an afternoon ceremony at the America Gardens Theatre, sessions on Epcot's history and queues for Epcot fans to pick up limited-edition merchandise.
"It contributed to the way I thought about the future," Youngs said.
The 45-minute ceremony included music by Mariachi Cobre and the Voices of Liberty. Walt Disney World President Meg Crofton recognized folks who were present on opening day in 1982 and introduced a parade of cast members representing the pavilions of World Showcase and the attractions of Future World.
An extended version of the park's end-of-night spectacular, "Illuminations: Reflections of Earth," is scheduled for 9 p.m. today.
Epcot, the second-oldest of Disney World's four theme parks, opened to the public on Oct. 1, 1982, exactly 11 years after Magic Kingdom debuted. It was originally known as EPCOT Center and served as an acronym for "Experimental Prototype Community of Tomorrow," a moniker created by Walt Disney for his idea of a futuristic, model city.
More than 10.8 million guests have visited Epcot in each of the past two years, according to the Themed Entertainment Association. That would make it the third-most popular theme park in the United States, behind Magic Kingdom and Disneyland in Anaheim, Calif.