Turning 18 is something you look forward to pretty much from the time you can remember. Every kid, tween and teen has, at some point, looked at their parents and said, "I can't wait to be 18 and out of this house!"

However, looking back at myself four years ago as a high school senior who was on the cusp of that "magical" age, I realize there was so much I didn't know and so many things I was literally unprepared for. I honestly wish now that someone would have told me what it's really like to be a grown-up.

So, without further ado, here's 18 things I wish I would've known at 18.

1. You still need your family.

I thought turning 18 would mean that I could go out into the world and handle everything on my own. I was going to be my own boss and handle things alone like a "responsible adult." The truth is, you still need your family. You still need support—whether emotional, financial or intellectual. Make sure to show your family that you value you them just as much now as you did in high school.

2. No one is going to come along and save you from your decisions.

You may still need your family, but the days of Mom and Dad calling the school or police station to bail you out are over. This means you have to pay attention to your actions more than ever before, because one decision as an adult can change your entire life (for better or worse!). Be mindful of the company you keep and the places you go; these reflect the type of person you are becoming.

3. You don't have to fit in.

High school is full of cliques, and everyone trying to be "popular." It's only natural to go into college acting the same way, but honestly: no one cares! (Or at least very few people.) Take this time to discover and redefine who you are; don't worry about judgment. Everyone is too busy with term papers to worry about what shoes you are wearing or what color your hair is.

4. Don't give it all away (unless you're 100 percent ready).

It's no secret that sex is a huge thing in high school and college. In fact, you've probably been teased at least once about having a crush on someone or been accused of hooking up with someone in your class. Don't make sex a competition. What you choose to do with your body is your decision, and no one has the right to pressure you. Just because your best friend has had four partners, that doesn't make you inadequate for never being kissed. Take time to understand safe-sex practices and discuss them with potential partners. When you're ready, you'll know—and trust me, it'll be awesome!

5. Make the most of every opportunity.

Keep an open mind. You're young—try new things. Studying abroad in Germany? Yes, please! Roommate's family invited you to try bungee-jumping with them? Heck, yeah! Even if the prospect of something is a little scary, at least consider it as long as it's legal and reasonably safe. You'll be glad you did when you look back!

6. Make sure you hit the books.

It can be so tempting to go out to parties every weekend and join every club that you encounter, but trust me: it won't be fun when you're hungover the morning before a final exam, or when you start failing chemistry because you can't get out of bed. Schedule time just for studying and stick to it. Your future depends on it.

7. The Freshman 15 is a real thing (and you can avoid it).

Let's be honest here: dining hall food isn't healthy. Not to mention, you'd be hard pressed to find an event on campus that isn't serving something full of grease or sugar. Even the most seasoned high school athletes often find themselves "battling the bulge," so to speak. The key to keeping the weight off? Regular exercise! Most colleges and universities offer free fitness facilities, and if yours doesn't, a few crunches and some jogging daily should do the trick.

8. People aren't going to take you seriously unless you prove they should.

This is a tough one to admit because you want to believe people take your opinions into consideration. You are an adult now, after all. However, the unfortunate truth is many people believe our generation is "entitled and uninformed." So how do you get people to think twice? Get involved in your community. Register to vote. Get a part-time job. Volunteer to help the less fortunate. Keep your grades up. The more "adult" things you engage in, the more people around you will see you as an equal instead of a child.

9. Money and possessions aren't everything.

Sure, money is great (especially if you work for it), and it's always nice to have an iPhone to play around on, but memories are priceless. Start spending less on things and more on experiences. Many colleges offer discounted tickets to concerts, sporting events, museums and more. After all, those $150 Nike's will wear out in a few months, but that Katy Perry concert you and your roomie scored tickets to? You'll be talking about it for years to come.

10. It's OK not to know

I saved this for last because this is the single biggest thing I wish more people would have told me. In my school, it was expected that you go to college the fall after graduation. I started freshman year studying communications...I ended up withdrawing and taking two years off before I finally found my passion. The good in it all was that I got to have experiences and travel to places I wouldn't have if I had been in school. The bad was the fact that everyone started to look at me as a slacker. That's not true. Take as much time as you need to be sure you're choosing the career path that is best for you. You don't want to spend time and money on something that will make you miserable.

With all this being said, I wish the best of luck to this year's graduating seniors. Each one of you had unique talents and a unique purpose in life. You may be only 18, but trust me: you willchange the world!