Bill Gates and Melinda French Gates Celebrate Daughter Phoebe's 21st Birthday: 'So Proud'

"Watching you do big things has never surprised me," the Microsoft co-founder wrote in a social media tribute

Phoebe Gates is celebrating another achievement — turning 21!

The Stanford University student, who is the youngest of Bill Gates and Melinda French Gates' three children, marked the major milestone on Thursday, and her parents were sure to get in on the well-wishes.

Bill, 67, shared a series of sweet throwback photo on Instagram for her big day, saying in the caption that Phoebe will "always be my little girl."

"Watching you do big things has never surprised me," the Microsoft co-founder added. "I’m so proud of you."

Meanwhile, in a FaceTime call shared on Instagram, Melinda gave her daughter advice for her 21st year. She told Phoebe to remember that she knows herself "a lot" and to not "ever forget who you are."

She went on to encourage Phoebe to "always keep" her trusted group of friends close. "That way you’re never going to go wrong in life," she added. "Happy 21st birthday. I’m so proud of you and I love you so so much.”

Related: Phoebe Gates Shares Glam Photos from New York Fashion Week — Including Snap with Mom Melinda French Gates

Jennifer, her older sister, also shared a series of candid photos of their close bond on Instagram.

"I couldn’t be more proud of you as a young woman, entrepreneur, best sister, friend and auntie," Jennifer wrote, including a reference to her own baby girl.

"Love you more than I can express, P, and will forever have your back," she added. "Now let’s celebrate."

For Phoebe, the past year has been one full of accomplishments.

Last month, Phoebe and roommate Sophia Kianni — who are teaming up to launch digital fashion platform Phia— debuted a limited-edition capsule bag collection in collaboration with fashion designer Stella McCartney.

Related: Phoebe Gates Addresses 'Misconceptions and Conspiracy Theories' About Her Family and Boyfriend

At the launch event for the collection, the college student was photographed with her mom and sister Jennifer Gates — both of whom appeared to be rocking handbags from the collection as they posed together.

Jennifer, 27, went on to share a series of smiling photos with Phoebe on social media.

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"Proud big sister moment," she wrote on her Instagram Stories. "Can't wait for the world to see what @phoebegates and @sophiakianni have built."

In an interview earlier this year with The Information, Phoebe hinted at Phia’s mission.

"We're building out an idea to help make fashion more sustainable. We have so much planned for this year," Phoebe said at the time.

Related: Phoebe Gates Wears Glamorous Dress in Photo from Night Out at Shawn Carter Foundation Gala

Over the past year, as Phoebe has also taken time to utilize social media for good — and to control her own narrative while in the spotlight as the member of a prominent family.

"People have a lot of preconceptions about me, so TikTok has been a chance for me to tell my own story and also use the attention my family name might bring to spotlight issues that are important to me, like women's health and sustainable fashion,” she told The Information.

In addition to posting an essay about the fight for reproductive rights, earlier this year she shared a clip of a "contraceptive talk" with her mother.

The former British Vogue intern has also made sure to not miss out on other family celebrations, whether it was the birth of Jennifer and her husband Nayel Nassar’s baby girl in March or her sister’s birthday a month later.

In April, when Jennifer turned 27, Phoebe posted a picture of them together at a fashion show as well as a childhood throwback photo.

"Thank you for teaching me the lessons I needed to know, speaking the truths I needed to hear, and of course showing me how to grow up. Happy birthday to the best big sister a girl could ask for," she wrote at the time.

Jennifer commented, "Love you the most P. Thank you😭💜."

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