Mrs. Obama used the early Cinco de Mayo celebration with students from two bilingual charter schools to remind the crowd about the outbreak in Mexico that has left 26 confirmed dead.
"At a time that we're celebrating Mexican culture and heritage it's so important for us to think about some of the challenges that the folks in Mexico are facing right now," she said.
The first lady told students from the Latin American Montessori Bilingual Public Charter School and The Next Step Public Charter School that the most surprising thing about her move to the White House is how much fun it is to be first lady.
The former lawyer and administrator said she loves her job because she thinks public service is very important.
"I wanted to make my career be something that helped others, and being the first lady is like the icing on the cake of helping other people," she said.
Mrs. Obama urged the older students to get involved in serving their communities, too.
"We are going to need you all to take on the next challenges of leadership," she said. "Think about a way that you can develop a career or have some time spent in your life to give back."
The first lady told the younger students they should understand that the institutions in the nation's capital such as Congress, the White House and the Supreme Court exist to work for them.
"It's important for you to understand what Washington is all about," she said, adding that she wanted them to feel that "that space is your space and that that's your democracy as much as it is anyone else's."
Students from the two schools performed traditional dances and a sang the LAMB school song for the first lady.