I turned 20 last year.

20.

That's t-w-e-n-t-y.

As a kid, I never really thought about what life was like as a 20-year-old. Aside from the exciting and highly anticipated 21st birthday everyone always talked about, I guess I just figured one night I'd go to sleep as a fun, carefree teenager and wake up as a boring, responsible adult.

I was wrong.

Sure, I always thought I was an old soul, but just because I preferred Billy Joel over the "The Bachelor" didn't mean I had any idea what life as an adult was actually like.

Since turning 20, I signed the lease for my first apartment, got my first office job, and got my first letter in the mail about setting up a retirement fund (help). Somewhere, in the midst of all this external change, my personal tastes started evolving, too. Here are 7 changes I noticed in myself that made me realize I'm well on my way to responsible adulthood (again, help).

1. You eat foods like tuna salad for lunch... on purpose.

www.istock.com

As a kid, I turned up my nose to type of salad, let alone tuna. This morning, I found myself reaching past the pre-packed Lunchables for a Tupperware container of tuna salad. At lunch today, I even found myself enjoying the concoction of tuna, mayo, grapes, and celery *shudders*.

2. Your find yourself shopping for "business casual."

www.istock.com

My summer shopping sprees no longer consist of searching for the perfect swimsuit or a new pair of sandals. Instead, I'm on the hunt for sales on khakis or a nice blouse.

3. A night in sounds more appealing than a night out.

Looking the tv at home

My high school summer nights rivaled the ones in movies, with long drives in the country, fireworks, and ice cream dates. I never realized how valuable those nights were. After a long day at work, the idea of getting ready all over again to be social when my brain is fried seems more daunting than dreamy.

4. You have to set aside specific time to exercise.

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Sure, regular trips to the gym is a healthy habit to start young. On the other hand, when I was growing up, I had cheer practice and gym class and bike rides to keep me active. Recently, however, I've come to realize that unless I schedule out time to intentionally move my body, I'll spend most of the day sitting.

5. Meeting friends for coffee is more normal than inviting them over for a sleepover.

www.istock.com

To make use of one of the world's most infamous clichés, it seems like just yesterday that I was telling my friends to hide somewhere in my house so that when their parents came to pick them up, they'd get to stay the night. I swear I blinked and my conversations went from, "Hey, wanna come spend the night?" to, "Hey, let's grab coffee and catch up!"

Sure, I miss staying up and talking about boys and eating way too much candy, but my new method of "hanging out" is much more conventional for my sleep schedule (and waistline).

6. You realize professional adults may not have their lives together like you thought.

www.istock.com

This may be one of the biggest wake-up calls of all. I don't know why I thought getting a full-time job and throwing on a pair of dress pants would mean my life was instantly put together. I guess I just always assumed adults didn't get nervous, always felt secure in who they were, and never had spontaneous dance parties in their pajamas.

Newsflash: Al of life's problems are still there and still very real. I'm starting to think no one ever really knows what the heck they're doing... but hey, that's what makes life fun, right?

7. A 9 p.m. bed time doesn't sound so bad.

There, I said it. My days of staying up until 3 and sleeping in until 11 are done. With 8 to 9 hour work days that start sometimes as early as 7:45 a.m., staying up until midnight is a challenge in and of itself. I find myself apologizing to my mom for all those years I gave her a hard time for going home from work just to fall asleep.

Overall, I am starting to find that the transition to adulthood may not be a clear-cut path from troubled teen to pristine professional. As long as I can still dance around in my pajamas, enjoying tuna salad doesn't seem too bad.