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When I turned 40 I became my father. Let me explain. For as long as I can remember, my father was half deaf and refused to admit it. When waiters at restaurants would recite the evening's specials, he'd lean in and wrinkle his forehead, or cock his head like a curious dog—and then insist he'd heard every word. Recently I asked my dad, who is now pushing 80 and just got double hearing aids, when he first realized his hearing was going. He thought for a moment, calculated, and then said, "About 40 years ago."

Welcome to middle age, when body and mind start acting up. They'll punk you at every turn because, evolutionarily speaking, you are old. Once you're past the age of procreation—IVF and other medical miracles notwithstanding—nature is no longer invested in making your skin glow or your boobs perky or in having you remember where you left your car keys.

And this is actually, breathtakingly liberating.

Here, based on 40-plus years of rigorous field research (aka living my life), is why.

1. You can trade a bikini for a caftan. 

When you were in the baby-making business, your body had an incentive to stay slim and sexy. You could eat things like pasta and pizza and, you know, food, and still look pretty hot. Now, you eat half a sweet potato and whoa, did the skinny jeans go through the dryer again? This decade issues an engraved invitation to stop wearing skinny jeans, thong undies, push-up bras and other tight, itchy, poking, rubbing, riding-up nonsense and instead, luxuriate in shapes and fabrics that make you feel comfortable at any size and do not require Hollywood tape or Spanx. And just as knowledge isn't wisdom, trends aren't style. You can be tremendously chic without wearing ripped jeans, cropped tops, and glitter eye shadow. Think of it as a get-out-of-jail-free card for your closet—and your hips. (But what's with that hair suddenly growing from your chin?)

2. Saturday night is just another day of the week.

No pressure to go clubbing at 10 PM or stay out drinking til dawn. Not just because you can't—you'd face-plant into your mojito just as the Millennials started arriving and still want to call in sick on Monday—but because you no longer want to. Your new ideal evening involves quality time with your people, your Kindle, Netflix, and probably a glass of wine or two. This new nightlife is umpteen times more rewarding at this point in your life—and there's no pricy bar tab, hangover, or Walk of Shame to regret. (Want to pick up some healthier habits? Sign up to get daily healthy living tips delivered straight to your inbox!)

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3. Your face is a work of art.

Instead of cursing the forces of gravity, you can now appreciate that the crow's feet, marionette lines, sun spots, freckles, and even acne scars you see in the mirror are proof that you've lived. You've smiled and laughed. You've winked and blinked and blown kisses, widened your eyes in surprise and cried tears of joy. This face has seen you through all the experiences of your life—good, bad, and it's complicated—and that richness is beauty. It's wisdom. It's personality. It's the face your children and your partner and your girlfriends have come to know and love.

4. You can let people help you.

My kids want to program my phone—great! I love having Siri be an Australian dude. A teenager wants to carry groceries to my car—you bet! My 40s have sparked an altruistic impulse in the people around me that in my 20s and 30s I might have resented, because I was too busy proving that I was strong, capable, and self-reliant. Now that I've hefted suitcases, sofas, and boxes of books (remember books?) from dorms to apartments to houses, and hurt my back doing...nothing, I don't even know what—I'm happy to have a helper. A hero, even. Once you're in your 40s, help doesn't mean you're weak; it just means you don't have to do everything yourself.

MORE: Love Your Age

5. You remember the good stuff.

So geometry fell out of my brain (if it was ever there in the first place), and I've long since forgotten how to conjugate in French. I go from room to room searching for glasses that are on my head. I forget my daughter's regular guitar lesson at least twice a month. Things I think happened 3 years ago actually happened 10 years ago. My ability to remember names has sunk so low—you might as well introduce yourself as "that woman with brown hair and cool boots that you met at so-and-so's house." I once heard that the brain purposely erases old memories to make room for new ones—because how could you ever find your car at the supermarket if you remembered every space you'd ever parked in! The way I see it, my brain cells are doing a stellar job of losing the proverbial parking spaces so it can lock in the highlights of four decades that bring me joy every day.

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6. You can finally relax.

By your 40s, most of the tumultuous, world-rocking changes are behind you. On one hand this means you'll probably never become president, an astronaut, or an Olympic downhill skier. But you're good at what you do. And you know who you are. And the rest doesn't matter so much. I sing in a rock band. I bake amazing blondies. I throw a kick-ass fundraiser that raises beaucoup bucks. I also have insanely frizzy hair, I'm horrible at math (see above), and I've given up on trying to enjoy classical music concerts (sorry, Dad). But I'm good at what I do. I know who I am, and the rest doesn't matter so much.

A new study came out today showing that the mid-life crisis is a myth; that the trajectory of happiness and contentment is a straight line going up. I may not remember why I walked into the kitchen, but my 11-year-old just texted, "Love you more than anything, Mommy," with hearts and cookie emojiis. So turning 40—it's all good. I can't wait to see what my 50s will bring.

This article originally appeared on Prevention.com.