The Obamas were married on October 3, 1992. But with the critically important first debate taking place Wednesday, dinner by candlelight was not in the cards for the first couple.
The showdown comes just 33 days before American voters go the polls on November 6, and was being held at the University of Denver.
Obama has said that he and Michelle will push back their anniversary celebration until the weekend.
The first lady declined to offer a critique of her husband.
"I really would probably be the worst person to assess his style or his techniques," she told CNN.
"There are the rules, and you don't want to clap... So I'm just trying to make sure I'm following the rules."
Michelle Obama and Ann Romney were both on hand in Denver for the debate, and the two women shared a brief embrace shortly before the event began.
Romney said her husband has followed a specific routine at the start of each of his 20 debates during the Republican primary race, and she expects him to do the same with the presidential showdowns.
"As soon as he gets on stage... he takes off his watch and puts it on the podium," she told CNN.
"Then he writes 'Dad' on the piece of paper," in honor of his father George Romney, who was governor of Michigan and also ran for president in the 1960s.
