Sasha Obama Turns 20! Mom Michelle Celebrates with Throwback Photo: 'You'll Always Be My Little Girl'

Michelle and Barack Obama celebrated daughter Sasha Obama's 20th birthday on Thursday with a throwback photo, fond memories and excitement for her future.

"Happy birthday to my darling Sasha! I am so grateful for every laugh we've shared - and everything you've taught me over the years," the former first lady, 57, wrote alongside a photo of her hugging Sasha as a child.

"You'll always be my little girl, but I couldn't be prouder of the woman you are becoming," Mrs. Obama wrote. "Love you so much!"

Former President Obama shared another birthday message, alongside his own throwback photo of him and his daughter.

"Happy birthday, Sasha!" the former president tweeted. "You've grown so much, and it's been a joy to watch you become the person we always hoped you'd be. Your mom and I can't wait to see where life takes you next."

Sasha is a student at the University of Michigan while big sister Malia Obama, 22, recently graduated from Harvard University.

Mrs. Obama said last month that she "almost forgot" her daughters were turning 20 and 23 years old this summer. (Malia's birthday is July 4.)

"I mean, I'm just like 'Stop there.' I don't even have teenagers anymore," Mrs. Obama said then, saying she was looking forward to what was to come.

The Obamas relished their extra time together at home last year amid the COVID-19 pandemic.

With their schools shut down to in-person instruction, Sasha and Malia both spent much of 2020 quarantined with their parents, splitting time between the family's Washington, D.C., home and their house on Martha's Vineyard.

Mrs. Obama told PEOPLE last year that Sasha, who recently completed her sophomore year, had become a "midnight baker" along with Malia and that the former first couple had enjoyed their daughters' unexpected time home from school.

"This time has allowed us to get some stolen moments back with our girls," Mrs. Obama said. "Those recaptured moments have meant the world to us and I think they've made our relationships with our children even stronger."

The former president also revealed to PEOPLE in November that Sasha and Malia had become more politically active as well - "without any prompting from Michelle and myself," he said.

President Obama said his daughter had participated in 2020 protests against police brutality and racial injustice in the wake of George Floyd's murder. He elaborated more on the "optimism" that gave him during an interview this week on CNN.

"What I find interesting is they're also starting to be very strategic about how to engage the system and change it," Obama, 59, told CNN. "They're not just interested in making noise, they're interested in what works."