First lady Michelle Obama is celebrating her 50th birthday with a blowout dance party. Here's a look at some of her best moves and grooves. (Julie Percha/The Washington Post)

When she was in high school and considering Princeton University as a college destination, Michelle Obama said, counselors warned her that she was too ambitious. “They told me I was never going to get into a school like Princeton,” she told a group of low-income students recently. “I still hear that doubt ringing in my head.”

As she settles into her husband’s second term — and celebrated her 50th birthday Friday — the first lady is using her life story to propel a major White House push to get low-income young people to go to college. Administration officials believe Obama’s biography — growing up in a working-class family on the South Side of Chicago — is one of the most powerful tools they have to increase the number of low-income children who make it to college.

The new focus marks a more personal approach for the first lady, who previously was less likely to discuss details of her educational background. It also moves her away from the relatively benign task of promoting healthful diets and exercise and into the fraught arena of education policy and connects her more closely to actions her husband is taking, some of which conservatives strongly oppose.

East Wing aides say Obama will meet with students nationwide in the coming year, focusing especially on sophomores who have the full arc of the college application process ahead. And she will talk to school counselors, teachers and mentors about how they can help steer young people to college. Staff members from her office are meeting regularly with Education Department officials.

Obama’s redefined role was on display Thursday during a White House summit of colleges and other organizations that promised to spend big money recruiting hundreds of thousands of low-income students to universities. The administration emphasized that the effort was jointly hosted by the president and first lady.

“The truth is that if Princeton hadn’t found my brother as a basketball recruit, and if I hadn’t seen that he could succeed on a campus like that, it never would have occurred to me to apply to that school — never,” Obama, a 1985 graduate of the Ivy League school, said at the event. “And I know that there are so many kids out there just like me.”

Former East Wing officials say tackling a high-profile policy area is full of potential land mines for first ladies — as Obama’s immediate predecessors, Laura Bush and Hillary Rodham Clinton, can attest.

“Education is a really tough issue,” said Bush’s chief of staff, Anita McBride, referring to the former first lady’s efforts to tout her husband’s No Child Left Behind initiative. “Inevitably, someone is going to be unhappy with what you’ve promoted. No matter what she does, she has got to always make sure it married up with the broader administration goals.”

President Obama has repeatedly clashed with Republicans over his education agenda, from the administration’s backing of Common Core curriculum efforts to his call for universal pre-kindergarten classes. In response to Thursday’s summit, House Republicans lampooned the president’s record on higher education by arguing that “college costs have skyrocketed under the Obama administration” — an assertion administration officials dispute.

Historians say that Clinton and Bush seldom channeled their life stories to advance a cause quite like Michelle Obama has. “Neither of them made reference to aspects of their own personal story in positioning intentions and ambitions with a public service project,” said Carl Anthony, a historian with the National First Ladies Library.

Using personal stories to promote public projects was more common in the past, he said, referencing Betty Ford’s advocacy for mammograms after receiving a breast cancer diagnosis and Rosalynn Carter’s work on mental health.

But administration officials say the first lady’s personal story is so powerful that it will inspire young people to seek college educations.

“This is her life. This is her reality,” Education Secretary Arne Duncan said. “And so what she does is just speak with unbelievable honesty and candor about what her challenges were. What her insecurities were. Things she did well.”

Added close friend and White House senior adviser Valerie Jarrett: “I think she’s such a good role model for young people because they can connect with her. They see themselves in her.”

In November, Obama began her education initiative before an auditorium of low-income students at Bell Multicultural High School in the District, speaking about her life’s journey.

“At 6 a.m. every morning, I had to get on a city bus and ride for an hour, sometimes more, just to get to school,” she said. “And I was willing to do that because I was willing to do whatever it took for me to go to college.”

After the event, students approached Principal Maria Tukeva with a lists of colleges they want to attend.

“I felt connected to her in some way because the things she went through I’m going through right now,” said Meroei Degefa, 15, a sophomore at the school, who wants to go to Johns Hopkins University or Georgetown University.

Obama emphasizes the challenges she had in common with the students she is trying to reach, such as having parents who did not graduate from college. But she also had advantages in her youth that many of the students don’t have.

Her brother, Craig Robinson, has described their Chicago childhood as “the Shangri-La of upbringings.” Their father worked for the city’s water system, while their mother — who attended two years of teaching college — stayed home with the children, Robinson wrote in his book, “A Game of Character.”

Obama has described herself as having been a serious student. She finished eighth grade as class salutatorian and was accepted to Whitney M. Young Magnet High School, a public school in Chicago. But unlike the troubled inner-city institutions many low-income students attend, hers was a college preparatory school.

She followed her brother to Princeton, where he was recruited to play basketball. She has pointed out that a high school counselor who didn’t think Obama was Ivy League material discouraged her from applying.

Obama has said that at Princeton, she felt as though she had landed on another planet. But in some ways, it was familiar: She was known as “Craig Robinson’s little sister,” and he was a basketball player as well as a DJ at the Third World Center, which served as a gathering spot for black students and international students.

“There were counselors and people who told me that I shouldn’t reach that high, that I didn’t have what it would take to get into a school like Princeton,” Obama said on a BET program late last year. “But I ignored the naysayers.”