updated 01/17/2014 AT 10:00 AM ET
•originally published 01/17/2014 AT 11:00 AM ET
First Lady Michelle Obama turned the big 5-0 on Friday, and showed off one of her first birthday gifts, courtesy of the American Association of Retired Persons: a free membership card.
“Excited to join Barack in the 50+ club today check out my @AARP card!” she wrote on Twitter next to a photo of herself grinning and showing off the card. Some 50-year-olds dread receiving it, but not Michelle!
“I don t feel that much differently than I did when I was younger,” Mrs. Obama told PEOPLE in advance of her big milestone. “What I hear is that age is a number, it s a state of mind.”
As for what President Obama might be wrapping in ribbon for the birthday girl today, “That’s top-secret,” he tells PEOPLE. “Not even the NSA knows that.”
For more of our interview with the First Lady – including her thoughts on Botox, menopause and becoming a grandma – pick up the latest issue of PEOPLE, on newsstands now.
FLOTUS (@FLOTUS) January 17, 2014