Kate Gosselin's Twin Daughters, Mady & Cara, Graduate High School

Kate Gosselin's oldest daughters just marked a major milestone. Mady and Cara Gosselin, the 18-year-old twin daughters of Kate and her ex-husband Jon, have graduated high school. Mady Gosselin announced the big news by posting an Instagram photo of herself dressed in all white as she smiled alongside two of her biggest supporters: her 15-year-old sextuplet brothers Aaden and Joel.

The Gosselin kids, who attend a private school near their home in Pennsylvania, posed in the hallway of their school as Mady celebrated her big graduation day. Mady did not post any photos with her twin sister or with her other siblings, sextuplets Alexis, Leah, Hannah, and Collin.

Many fans of the Kate Plus 8 stars posted in the comments section to offer Mady and Cara Gosselin congratulations and to ask them where they are headed for college.

It is unclear if Jon Gosselin attended the graduation ceremony for his twin daughters, but the DJ has made no secret of the fact that he has a strained relationship with several of his kids. Jon did not post congratulations to Mady and Cara, and Kate Gosselin also let the day go by without commemorating it on social media.

You can see Mady Gosselin's sweet photo from her graduation day below.

Kate Gosselin recently talked about her daughters going off to college. At the Television Critics Association Winter press tour earlier this year, Kate said her eldest daughters are both good girls, so she doesn't worry about them.

"I think that they're such good girls that I don't have to keep after them," Kate told reporters, per E! News. "They're self-driven. They have goals and dreams, and they're just good kids."

Of course, Mady and Cara's upcoming move to college is also what helped spawned the family's upcoming TLC reality show, Kate Plus Date, which will follow the mom of eight as she dives back into the dating pool 10 years after her divorce from Jon. Kate Gosselin told People that her kids are worried about her being alone once they head off to college, so they want her to find a life partner.

"As we're talking about Mady and Cara going off to college which is becoming more and more of a reality, it's gonna happen, it almost became like a worry for them, too, like 'Mommy, you're gonna be all alone soon,'" Kate told the magazine. "But it was very apparent, now that they're older and talking about dating and how they're all gonna get married someday … it became apparent… they want me to have somebody in my life."

Mady and Cara are the only two Gosselin kids who will appear on Kate Plus Date to help their mom navigate the dating scene. Kate said that once the twins head to college next fall, it's "absolutely up to them" if they want to continue on the family's reality shows or star on a spinoff about their college lives.

Kate Plus Date premieres June 10 on TLC.