Other 18-year-olds might be heading off to college in September, but Justin Bieber will continue singing Baby... baby... baby. Although this 18-year-old is king of the teenyboppers, he is out to prove that he is all grown up -- drinking beer, driving fast cars and defending curvaceous sex-tape-making reality stars.

GQ magazine interviewed Justin Bieber, who is now technically an adult in the legal system, to find out the answer to a particularly pertinent question Is he a man? GQ sent Drew Magary out with the Canadian superstar to spend a night in L.A. with him the day after his 18th birthday.

Magary's first impression? Justin Bieber is a very small human being. He's 18, but he could easily pass for someone six years younger. His rep says he's five feet nine, but he looks about four feet four, maybe one hundred pounds.

Justin Bieber might be small but his bank account is huge.

The Boyfriend singer rakes in $55 million a year and is ranked No. 3 on Forbes' World's Most Powerful Celebrities list. His garage has a Porsche Turbo, a Range Rover and a Ferrari in it. Oh, and he drinks beer.

For me, it's just like, I like to be in control of myself. I mean, I've had a beer, like, before.... But I never get out of control, he told GQ about his experience with adult beverages (even though he is not yet at the legal drinking age).

I mean, I keep my guard up a lot, because you know, you can't trust anyone in this business, Bieber said. That's what's sad. You can't trust anybody. I learned the hard way.

Show business is certainly not easy and Bieber is quick to defend his fellow celebrities who might unnecessarily get a bad rap.

Take Kim Kardashian, for instance. When Bieber's friends made fun of the reality diva, the teen does not let them off without a fight.

You guys are so mean bro... People say she doesn't do anything; she actually does do stuff ... she works hard, Justin Bieber said to his friends who were joking about her during his GQ interview. Maybe that photo shoot the two did together back in 2010 really left an impact on him.

Beers and babes aside, Justin Bieber is quite private about his personal life with girlfriend Selena Gomez.

Like every other teenager in the universe, Bieber evades questions by staring directly at the floor, GQ's Magary quipped.

Despite being tight-lipped on Gomez, the pop star is quick to emphasize his maturity. Bieber has said that, even though his fan base is young, he hopes to grow with those fans, create good music and become a more mature artist, the Huffington Post reported.

What better time to get the ball rolling than at 18?

I'm a swaggy adult, he told GQ.

But Drew Magary did not seem to be too convinced. Yet.

The label's mission is to make a man out of Bieber. The only person who isn't ready to make a man out of Bieber is Bieber. He wants to be 18. He wants to be a swaggy bro-he seems incapable of being anything else-and that's as it should be. Manhood can wait.