Growing older with grace, our lives only go in one direction so let’s make the most of it.

They say 50 is the new 40. It isn’t. It’s just a different 50. I’m not 50–I am, as we say, 50ish. The mid-50s. Anything but the actual number.

I had a birthday at the end of February and I have never been so aware of aging. Oprah turned 60 a month before my birthday. Oprah. 60. She did what Oprah does, said it was fabulous and freeing and wonderful.

Just like she did when she turned 50. But I could suddenly see that age was beginning to set in her face, around her eyes, in that crease on the right side of her face where she must sleep every night, because I have a small one myself, on my left side.

Two weeks before Oprah’s birthday, Michelle Obama turned 50. She had her dance party at the White House. She looked fantastic. She held up her AARP card for the cameras. When I look at Michelle Obama, I think maybe 50 is the new 40.

In the weeks and months before my birthday, I had written what seemed like a plethora of obituaries of women writers, notable among them Doris Lessing and Maxine Kumin. They were each 88 at their respective deaths and I thought, as one does if I live that long, how many years do I have left?

The fact is, 50 is a demarcation. I saw that vividly between Mrs Obama and Oprah. That decade difference is significant. At 50, you can still claim middle age, even though you’ve crossed an invisible line.

Yet 50 still puts you on a downward spiral. More years have passed than you have left to live. It needn’t be fast–it’s not a plummet from 50 to 80. But you know the years you have left, however many they are will be fraught at some point by illness, infirmity and frailty. That itself is daunting.

My partner and I are the same age. We went to high school together. I am a month older than her. So we are aging together. Just as we grew up together. We’ve known each other since we were fresh-faced, longhaired, mini-skirted 14-year-olds.

We were lovers in high school, briefly. Then again in college, briefly. And in this, our final incarnation, we celebrated our 15th anniversary as the first lady was turning 50.

I remember my partner’s young body as I remember my own. There are photos all over the house of me at various ages, from baby to toddler, grade school to high school, college and beyond.

My hair was white blonde in the early photos, then a deeper honey blonde. Now it is white blonde again, the front white, underneath the colour it was when I was younger.

I learned early that the sun and I would never get along, so my skin is remarkably unlined, except for that small sleep crease and a small furrow between my eyebrows. But despite the good skin, I inherited from my mother, I know I look my age or close to it, as does my partner. Because 50 really isn’t the new 40, and we are aging.

I’d like to say I’m fine with getting older, that heading into menopause doesn’t make me feel some sadness, along with the hot flashes. I’d like to say I didn’t wish I looked closer to 40 than 50. I’d like to read from Oprah’s script. Or the First Lady’s.

I’m trying. I hear a clock ticking in the distance and I feel that I need to meet its challenge. Stuff my life as full as I can. But maybe I need to let life stuff me full.

I’ve got time.

Here’s how 50 is the new 40: Women are living longer. U.S. mortality statistics now give women a life expectancy of 82 years. In 1930, that number was vastly different: 60. Oprah would already be dead because that number was even lower for black women–49–which means Michelle Obama would also have been dead.

So since 1930, all women have gained another 20 years of life. Twenty years. Think what 20 years means: If you’re 30, that’s your life since 4th grade. If you’re 50, it’s all the years since 30. Twenty years is a lifetime, a generation.

Not all of us will get those extra decades. Some of us will die of cancer or a sudden heart attack or a car accident–the leading causes of death for women under 50. But the likelihood of us living to 80 looms larger than the possibility we won’t make it much past 50.

My partner and I sometimes talk about aging and about how, if we’d ever thought we’d live past 30, we would have taken better care of ourselves. We’re only half-joking. When I was 20, I thought I would live forever. “Self-care” wasn’t a term in common parlance, then. When I was 26, I was diagnosed with cancer and the next few years were a series of operations and treatments. When I finally felt better, I felt I needed to live like every day was my last day.

That’s exhausting.

My father used to tell me, “Do as I say, not as I do.” So I am telling you the same thing: Plan for 50 and 50 really will be the new 40. Plan on a long life, because in another decade, we’ll have tacked another incremental few years onto the life expectancy. Plan on keeping your body and mind fit, because you’ll need both.

Taking care of your body is simple: don’t smoke and don’t drink or eat to excess. Exercise at least three times a week. Walk, don’t sit. Eat fresh fruits and vegetables. Stay away from too much meat and too much sugar. Drink lots of water and not too much alcohol.

Forget vitamins except for D. Exfoliate and moisturize, wear sunscreen and don’t get sunburned. Don’t have unprotected sex. Use lube because unlubricated sex breaks down the walls of your vagina. If you don’t have a partner, masturbate, because it’s one of the best relaxation tools. Sex keeps us young. Get enough sleep.

Taking care of your mind is harder. Read. Learn a second language if you don’t already know one. Do crossword puzzles or Sudoku, play Scrabble or chess. All these things use the parts of our brains we let be lazy. Keeping your mind sharp will mean your older years could be your best.

Meditate. Do yoga or Tai Chi. These things will help you to live better and longer because mindfulness keeps you strong in all the ways that matter.

Delete the toxic. If there is anything I have learned over the years, it’s how much damage toxic people and situations can do. They damage our immune systems, predisposing us to illness or autoimmune problems. They make us angry, hurt, sad, depressed. No to the toxic.

Be a friend. Be social. Studies show that women who have ten close friendships live longest.

Don’t be angry. Cortisol destroys our bodies and ravages, women, more than men. Every time you get angry it courses through your body. Let it go.

Don’t have regrets. When you hit 50, regret smacks you in the face like a dead fish. As young, as you can (start right now!), do the things you want to do. Don’t put your life on hold until some distant future that may never come or not afford you the luxury to make big moves or changes.

Volunteer. Studies also show that helping others releases endorphins—just like sex and chocolate and cocaine (no cocaine!) Plus at some point, there will be that obituary and you want it to be full. You want to leave a legacy.

Love your own body. I’ve spent years hating my body—and at each next stage of my life, I have looked at earlier photos and wondered what could I possibly have found fault with? Why couldn’t I see my own loveliness? Own your body, whatever its size or shape or colour. Own it and cherish it and don’t tell yourself it’s not good enough. It belongs to you.

I wish someone had given me a road map when I was 20 about what would be most essential to make my life rich and full and long. Some of it I knew instinctively, like having friends and giving to others. But when I turned 50, I still had not learned to love myself. That isn’t narcissism—it’s acceptance. It’s being comfortable with who you are. It’s not caring what other people think as long as you know you are on the right path.

There’s no perfect template to follow. But there is one goal: contentment. That’s what you want. You want to move into the second half of your life as close to content as possible; the first half is prep for that. You want to share as much as you can, embrace yourself, and try hard to do everything on your bucket list.

We have 20 more years than our mothers or grandmothers were given to live. That’s huge. That’s awesome. Don’t worry that 50 is the new 40 is the new 30. Just go for that best life: a body you love, a mind that’s sharp, people you love who love you back.

That way when 60 hits, you can be like Oprah (albeit without the billions)—ready to relax, breathe deep, have life flood up around you. Like acceptance. Like love. Like the life, you knew you always, always wanted to be living.