Arianna Huffington turned 70 on Wednesday. Sheltering at home, she used the occasion to reread her own journals dating back to when she was in her 20s. She found herself wishing she could give some advice to her younger self. Since she can't, she's sharing some of those insights with Thrive Global readers instead.

You can read her full, and heartwarming, piece here. These are a few of the biggest lessons the 70-year-old Arianna wishes she could share with the 20-something Arianna.

1. Stop worrying so much.

Huffington quotes Montaigne: "There were many terrible things in my life, but most of them never happened." She notes that the same has been true in her own life--most of the things she worried hardest about didn't come to pass.

I hit a milestone birthday myself recently, and I can attest to Huffington's observation, because the things I've worried about most so far in my life didn't happen either. And most of the bad things that did happen, such as my husband's heart attack three years ago, were things I hadn't worried about at all. (Before January, did you ever worry about a global pandemic?)

This may sound like you should take in a broader scope and try to worry about even more stuff so as not to be caught off guard. But Huffington is suggesting the opposite. Since we can't foresee or prepare for every bad thing that could happen, we're best off taking sensible precautions and trying not to worry about the rest. Because worry itself costs you time and energy that could be better spent elsewhere, and it can even affect your health. Huffington writes that she was struck by how depleting her worrying was and by "how little those worries and fears turned out to matter."

2. Focus on what really matters.

Reading her old journals, Huffington was struck by how good she was at understanding what was really important quite early in life but how bad she was at acting on that knowledge. She doesn't provide specifics about what she considered important back then but failed to prioritize. But in a way, it doesn't really make much difference. What mattered to her then or matters to her now is different from what matters to you or me or anyone else. We each have our own set of things we truly care about.

The lesson here is that we should all take a step back every now and then and consider how what we're focusing on fits into our biggest priorities, if it does. That was the point of Steve Jobs's famous daily question: "If today were the last day of your life, would you want to be doing what you're doing?"

Huffington says she wants to tell her younger self to "just go ahead and take that risk." That might be good advice for all of us.

3. Don't think of aging only in terms of loss.

We tend to think of aging in terms of the things we can't physically do anymore, the loss of things like our hair, and the knowledge that we have less lifetime ahead of us than behind us. But as Huffington reminds us, as we age we also gain things like wisdom, serenity, experience, and skill. "At 70, I followed my heart's desire without overstepping the line," Confucius wrote, and at 70, Huffington seems to be following her own heart's desire, running Thrive Global, which she started at 66.

This is what she says she loves most about being 70: 

"Being fully engaged building a company around one of the coolest challenges we are facing--changing human behavior so that we can lead healthier and more productive and empathetic lives--alongside amazing people, many of whom are less than half my age. And doing it with more joy, less stress, less sweating the small stuff, and without being frenetically obsessed with every hourly result."

If 70 means you can be fully engaged in work that you love with "more joy, less stress, less sweating the small stuff," then that sounds pretty good to me.