Christian said she worked to mobilize voters for Obama's re-election and was thrilled to celebrate the inaugural.
"It just makes me feel like I'm a part of something wonderful," she said.
"Instead of being considered a second-class citizen, we all have it going on now," added Christian, who is black. "We all can stand up and be proud."
Keeping an eye out for the unusual, Pretzer spotted a man pulling two life-sized cutouts of the president and first lady on a cart through the crowd. He flagged down Ian Davis, 43, of Baltimore and asked whether he might donate the cutouts later.
Davis had been allowing visitors to take pictures with the "Obamas" for a donation.
"You gotta make a dollar," he said, adding that he hauled the cutouts onto the National Mall "so I can see it, be it and participate."
Police eventually kicked him off the mall for asking for money. Now, Davis' cardboard images might be fit for a museum. He said he would donate them if his wife approves.
The museum has amassed more than 300 Obama-related items, including furniture from a 2008 campaign office in northern Virginia and a cloth banner from Tanzania with an Obama portrait and message reading "Congratulations Barack Obama."
When the museum opens in 2015 near the Washington Monument, one floor will be devoted to a chronology of African-American history, from 16th century slavery through the Civil War, Reconstruction, the civil rights era and beyond. The timeline will end with Obama and the 2008 election as a symbolic moment.
"Portraying a living individual is always more challenging," Pretzer said. "You don't have the perspective, and you don't have all the evidence."