Michelle Obama on hitting 50: 'The sky is the limit'

Michelle Obama
First lady Michelle Obama speaks at an event in the State Dining Room of the White House on, Sept. 18, 2013, in Washington.

On the verge of her 50th birthday, first lady Michelle Obama says she remains committed to her health -- which means more yoga, less cardio, and maybe even a little Botox down the line.

In an interview with People Magazine, Obama said she doesn't "feel that much differently" than she did when she was younger, even as she approaches that major milestone. 

"I'm more self-assured now," she said. "Each decade just brings a greater sense of calm and certainty and maturity and confidence that there's just no way you have that when you're 20."

But how will one of the most publicly health-conscious women in America -- known for her great arms and fitness face-offs -- stay fit at 50?  

"I don't obsess about what I eat, but I do make sure that I'm eating vegetables and fruit," she said. "And as everyone knows, I do exercise. I'm seeing myself shift from weight-bearing stuff -- even though that continues to be important -- and the heavy cardio and running, to things like yoga that will keep me flexible."

One of the most admired women in America also won't rule out plastic surgery for her future beauty needs. 

"Women should have the freedom to do whatever they need to do to feel good about themselves," she told People. "Right now, I don't imagine that I would go that route, but I've also learned to never say never."

When asked if she believed she had already reached her "peak" the first lady hedged her answer, but still sounds quite optimistic about the future.

"I don't know," she said. "I mean, I'm the first lady of the United States of America -- that's pretty high up. But I've always felt like my life is ever-evolving. I will be in my early 50s when I leave here, and I have so much more that I should do. I don't have the right to just sit on my talents or blessings."

"I've got to keep figuring out ways to have an impact -- whether as a mother or as a professional or as a mentor to other kids," she continued. "When we leave here, Malia will be in college; Sasha will just have a couple of years left, and then she'll be in college. At that point in life, whoa, the sky is the limit!"

While it may still be years off, Obama is looking forward to being a grandmother. 

"I want to be the grandma that my mom has been," she said, referring to her mother, Marian Robinson, who has lived in the White House and helped care for Sasha and Malia over the last five years. 

The first lady will celebrate her birthday with a fit-friendly White House dance party that her husband is throwing for her this coming Saturday.

Obama's full interview with People hits newsstands across the country on Friday.