The Gosselin Twins Just Turned 18 Years Old & They Look So Grown Up Already

If you're like me, then watching TLC series about large families and/or families with multiples is endlessly fascinating. I can't get enough of shows like Counting On and Sweet Home Sextuplets. But back in the day, Jon & Kate Plus 8 was totally my jam. Because I didn't bother to continue watching after Jon and Kate ended up divorcing, the eight Gosselin children have seemingly grown up overnight. In fact, Jon and Kate Gosselin's twins, Cara and Mady, are 18. And you won't believe what they look like now.

Honestly, the Mady and Cara I picture in my mind still more closely resemble that of the early Jon & Kate Plus 8 days. The TLC series premiered back in April 2007, according to E! Online — when the twins were only 7 years old. It was a much simpler time, for sure. Jon and Kate were still married, and although they were busy keeping up with six three-year-olds and two 7-year-olds — their biggest dilemmas at the time were probably sibling squabbles and potty training. In my mind's eye, the throwback photos below are what Cara and Mady still look like. (Which both happen to be last year's birthday messages from Jon and Kate.)

However, as it turns out, the twins are officially adults now. That's because they celebrated their 18th birthday on Oct. 8, according to Us Weekly. And if you haven't kept up with the Gosselins much over the past 10 years — or even the past 5 years — then you might not even recognize them today. Here's a photo of the twins from a February 2017 episode of Kate Plus 8, just to warm up. (But still, this was more than two years ago.)

In honor of the twins turning 18, both Kate and Jon took to Instagram to mark the occasion on Monday, Oct. 8. Mama Kate actually shared two posts dedicated to Mady and Cara. “HAPPY 18th Birthday, Cara and Madelyn! There are no words to describe how proud I am of you both," she wrote, alongside a photo of their birthday cake, People reported. "Despite the many turbulent times you’ve had to deal with so far in life, you have emerged as wise, level headed, reasonable, forgiving, loving, kind and absolutely brilliant ADULTS! I can say that I’ve poured endless love into you and fought tooth and nail for the best for you, but I cannot possibly take credit for the truly wonderful humans (adult humans!) you have become!” Kate continued:

You will thrive in life, I am certain, and I will still be with you every step of the way going forward, continuing to guide you and love you. I love you both so very very much and I wish peace, happiness and the great successes I know are coming your way!

Later on in the day, Kate also shared a photo of her daughters smiling and posing with "18" balloons. Just look how grown up they are!

For the record, Jon Gosselin shared a special message to the twins on their big day, too.

Even with photo evidence, it's still hard for me to believe Mady and Cara are seniors in high school and are officially adults. (And if it's what they want to do, they could be starting college next fall!) But I guess that's what happens when you don't tune into a reality TV series for a decade; kids grow up. Now that I'm a mother myself, I'm learning that it all goes by even faster when it's your own children — which is definitely a scary reality.

I know it's a day late by now, but happy birthday to Mady and Cara Gosselin! Welcome to this whole "adulting" thing, ladies. It's gonna be a wild ride.