60 is the new middle age: Here's why it's awesome

Looks like 60 is the new 50!

According to a study published in PLOS ONE, those celebrating their sixth decade should no longer considered old, but rather, middle-aged. The study reveals that age can be measured as time lived or it can be measured as time yet to live, based on the current human life expectancy.

That's why researchers from Stony Brook University and the International Institute for Applied Systems Analysissay that age measurements that have traditionally categorized people as "old" at a certain age (often 65) must shift accordingly.

Celebrating the milestone birthday this year? You're in good company. Among the stars that turned 60 over the last year were Ron Howard, Michael Moore, Jerry Seinfeld, Howard Stern, Oprah Winfrey and Al Roker.

This week, Reba McEntire, who just turned 60, told TODAY, "It felt wonderful!"

And, according to a TODAY survey from 2014 in which about 1500 adults ages 45-69 were polled, the 60-year-old demographic was overwhelmingly positive about their health. 14 percent rated it as "excellent," 61 percent rated their health as "good," and only 4 percent rated their health as "poor." 22 percent rated it as "fair."

Additionally, nearly three-quarters of those in their 60's reported that they were "embracing" their age.

To celebrate the recent changes in age perception, check out our favorite quotes about growing older and the great six-oh.

"I have no reservations about it. It is a milestone, but I'm happy, healthy and very lucky...I really do think 60 today is different from what our parents' 60 was. I feel like I'm going faster than ever. I think [at] 50, you're kind of hitting your stride, and I think — all things being equal — at 60, you're cruising. You literally are cruising now, and if, God willing, your health stays good, you know, you just keep moving till the parts wear out...As you get older, you know inherently that time is going to be compressed. I want to fill that time up with as much positive and as much good as possible." – Al Roker, TODAY Show host, on turning 60 in 2014.

"I'm coming up on 60, which is a strange thing, because when you're a kid you think, 'Sixty, that's ancient!' And then you're actually living in a 60-year-old body, and yeah, it is kind of ancient! But I feel just the way I always have." – Annie Lennox as told to Yahoo Music, on turning 60 in 2014.

"I may be a senior but so what? I'm still hot." – Betty White, actress and television personality.

"Some days it rattles and shakes in there psychically, but ultimately I feel nothing but a great gift of life. There's nothing to prove. I feel comfortable in my own skin." – Pierce Brosnan, who turned 60 on May 16th, 2013.

"Age is strictly a case of mind over matter. If you don't mind, it doesn't matter." – Jack Benny, comedian and actor.

"60 rocks!" – Actor and singer David Hasselhoff via Twitter in 2012.

"I'm sixty years of age. That's 16 Celsius." - George Carlin, comedian, actor, and author.

"I'm loving every minute of it...I'm very blessed. I thank the Lord every morning for letting me walk and talk and do what I get to do." – Country singer Reba McEntire on The TODAY Show in 2015.

"When you're young, you never think that someday you're going to be 60, so then when it actually does happen to you, you're simply stunned, which is ridiculous because you've had six decades to prepare for it! In my heart of hearts, I feel like I'm 28, but my thighs tell a different story. So I ignore my thighs and everything else that's fallen apart and I try to stay creative. I really do think that's one of the keys to happiness: Keep doing what makes you happy, keep impacting lives and keep creating something beautiful so you won't be temped to fixate on your face. And keep laughing!" – Kathie Lee Gifford on TODAY.com. The TODAY Show host turned 60 on August 16th, 2013.

"You are only young once, but you can stay immature indefinitely." - Ogden Nash, 20th-century American poet.

"At age 20, we worry about what others think of us. At 40, we don't care what they think of us. At 60, we discover they haven't been thinking of us all." – Eppie Lederer, 20th-century American advice columnist, under her pen name, "Ann Landers."

"I'm actually excited about turning 60. I feel of top of my game." – supermodel Christie Brinkley, as told People Magazine in 2014.

"In France, we have a saying 'life starts at 50,' and all surveys show we are the most satisfied in our 60s. We have a lot to offer, and the sky is the limit." – Mireille Guiliano, author of French Women Don't Get Facelifts, as told to New York Daily News in 2014.

"Sixty. I'm turning 60 this month! I'm so glad I've lived long enough to say those words and celebrate their meaning. I'm turning 60. I'm alive. Healthy. Strong... I approach this milestone, the landmark of 60, with humility, supreme thanksgiving, and joy. Knowing for sure grace has brought me safe thus far, and grace will lead me home." – Fame talk show host Oprah Winfrey, as told to Oprah Magazine. She turned 60 on January 29th, 2014.

"Laughter is timeless, imagination has no age, and dreams are forever." – Walt Disney, famed 20th-century animator, cartoonist, and film producer.