The singer confesses to an inaugural ball panic attack, and shares her new priorities

Even Sasha Fierce, it seems, has moments of weakness.

Before Beyoncé Knowles performed “At Last” for Barack and Michelle Obama’s first dance as President and First Lady in January, the singer – who has said her onstage alter ego is the aggressive Fierce – was overcome by emotion.

“I had to tell myself, ‘They asked you to do this. You have to do a great job. This is their history. Calm down. Calm down,'” she admits in the June issue of Marie Claire. “I barely made it. Literally seconds before the song started, I was crying like a 5-year-old.”

But she remains proud of that moment – and all of her accomplishments so far. “Fifteen years from now, I want to be able to look back and say ‘Wow.’ That’s where I was at 27. That was my best.”

And it certainly has been a big year: Last April, she married Jay-Z, 39, and the busy couple work hard to spend time together. “We try to sync our calendars,” Knowles says. “I started working on my tour a year ago just to make sure that I had time at home. But you know, that’s part of it. Any other woman who has to go to work and pick up the kids and make dinner – that’s way harder than what I have to do. At least I can say I’m taking two weeks off and really take two weeks off.”

She might even be ready for a longer break. “My priorities are slowly changing,” she reveals in the interview. “So after this tour I might be tired and want to take two years off. I’ve worked hard enough to be able to do that. I’m in a very good place.”

Who also might welcome a break from touring? Her mother, Tina, who accompanies her on the road. Tina tells the magazine, “I’m always the person to make her go to bed.”