I suppose you're officially grown up when:

• You know you're never going to live with your parents again.
• You know that you can always get a job if you really want one.
• You're not an idiot with money.
• You're able to be in a healthy, stable relationship.
• You're OK with how you look.
• You are worldly and culturally aware.
• You feel like you've been at least moderately productive with your life so far.

So I'm there. I feel like I got there in my late 20's.

I just turned 30. Never thought it was a big deal to turn 30. I mean, one day separates your 20's from your 30's, right? There shouldn't be any difference between me two days ago and me today. But then I DID turn 30. And suddenly, I've become conscious that the clock is ticking. And that has made me think. Deep stuff.

You know 30 is old when people say things like, "Wow, you don't look 30!" Thanks for the compliment. It's nice to know that I still have my youthful good looks. But if you break down that comment, their compliment is really a statement about how 30 is old. If they didn't think 30 was old, my youthful looks would be irrelevant. Know what I mean?

The aging process has been gradual. I DO feel fortunate to look young, but there are one or two new gray hairs every day. And I'm not as resilient. It used to take a good night's sleep for the soreness to go away after a baseball game, but now it takes at least a couple of days.

At the same time, turning 30 is kind of refreshing. Suddenly, it feels like I can leave a lot of the bullshit behind and start acting like an older person. Stop stressing about petty things. Go out to drink and party every once in a while instead of every chance I get. Value my real friends, and get rid of the flaky ones. Be productive. Start crossing things off my life's "to do" list that I've been putting off for years. There's a certain satisfaction that comes with deciding that you're going to start doing things with your life that really matter.

And this is where I really started thinking about things. What is it that really matters to me? How should I live the rest of my life? The clock is ticking, and my time is suddenly a little bit more valuable. I need to start figuring this stuff out.

Yes, life is about fun. No regrets. Live each day as if it was your last. Carpe diem, and all that. But is it just about having fun? Taking chances? Making lots of money? Making lots of babies? Surrounding yourself with people who love you? Fun and money and people who care about you can make you happier, but is life really just about being happy? Is there a bigger purpose?

Then it hit me. Life is about making a difference. Someone who has led a good life will have made the world a better place. Otherwise, what's the point of being here? What's the point of taking up space in the universe if you're not going to make the universe a better place to live in? If I go out and have a great time getting wasted on a Saturday night, is it going to matter to anyone in 1000 years? No. And when I'm on my deathbed, am I going to be happy knowing I had fun? No. I'm going to be wondering if I made a difference in the world. Did I matter? Did I make the world a better place?

We're paying rent, and we need to do a bit of renovating to increase the value of this place. If you can be happy and have fun and surround yourself with people who love you along the way, then you've got it made.

I revisit a quote by Ralph Waldo Emerson:

To laugh often and much; to win the respect of intelligent people and the affection of children; to earn the appreciation of honest critics and endure the betrayal of false friends; to appreciate beauty; to find the best in others; to leave the world a bit better, whether by a healthy child, a garden patch or a redeemed social condition; to know even one life has breathed easier because you have lived. This is to have succeeded.

So how can I make a difference? I don't know. Maybe I'll know by the time I turn 40.