For Meri Brown, this is just the beginning.

Yes, she's been a main cast member on Sister Wives for over a decade.

And, yes, she just turned 50 years old.

But if you think she's now some ancient reality star... if you think the best days are behind this plural marriage practitioner... well... you clearly have no read her latest Instagram posts.

First, Meri celebrated this milestone birthday about 24 hours before it became official, writing as a caption to the selfie below:

"I'm not freaking out, I'm not sad, I'm not struggling with it, it's been a good decade!

"The past 10 years I've watched my kid grow up and finish college, both undergrad and masters, and find an amazing partner, plus a couple cute puppies too!

"I've moved a few times, won a lawsuit, wrote a book, made tons of friends across the country, and started a couple thriving and successful businesses.

"I've traveled, a LOT, seen many amazing places across the US and some out of the country too."

Yup. Amazing partner.

We strongly assume this is a reference to Kody Brown, who Meri gushed over in December in response to rumors of the couple's demise.

"I've made the BEST of friends," added Meri, concluding as follows:'

I bought my old family home to share with my extended family (25 year dream come true). I've sung on a cruise ship.

I've danced under the stars. I've swam with dolphins. I've climbed mountains. I have nothing to complain about, it's a good life! Can't wait to see what the next decade brings!

Then, in a follow-up message she penned after turning 50, Meri took a deeper and longer look ahead.

"This is 50.

"This is 50 years of living, of hope, of love, of experience. It's 50 years of ups and downs, amazing days, sad moments, fabulous adventures, disappointing setbacks."

Previously, we thought a divorce or break-up would be on tap for Meri.

But it doesn't sound that way any longer.

In her new post, Brown went on to tell her followers that she's happy and excited about what's ehad -- and she is also "strengthening myself for the challenges that I know will come."

Professionally-speaking, perhaps?

Meri did not specify.

She simply said she is not shying away from them," adding online:

"I'm not backing down from a challenge. I'm throwing myself into my fifties with determination, with grace, and most importantly, with love.

"Bring it on fifties, I'm here for you!"

Whar a great attitude!

For the record, meanwhile, TLC has not yet renewed Sister Wives for a new season.

Despite faltering ratings, however, it's a pretty safe bet the show will be back.

We'll let you know when an announcement is made.