Justin Bieber's sound isn't the only thing that's changing as he grows up. The 18-year-old, who recently released the slower jam "Boyfriend," is transforming more every day from the little guy fans met on YouTube in 2007 into ... a very rich man, albeit still with perfect hair. As Bieber reveals in a new interview with GQ, he's even (shock of all shocks!) tried alcohol before, although of course he's under the legal drinking age of both the U.S., where it's 21, and his native country of Canada, where it's 19. But, as Bieber insists, he doesn't get wasted. "For me, it's just like, I like to be in control of myself," he tells the magazine. "I mean, I've had a beer, like, before … but I never get out of control." (GQ writer Drew Magary tried to entice Bieber to meet him at an adult venue such as a bar or a strip club for the interview, but his handlers nixed those ideas and opted for a recording studio instead.) More Photos from Justin Bieber's GQ Photo Shoot The Biebs has also learned to be disciplined when talking with the media. He rarely says much about his famous girlfriend Selena Gomez, 19, who's been spotted with him on the red carpet, vacationing in exotic locales, visiting his hometown in Ontario, Canada, and dining out at their favorite restaurant, IHOP. Unfortunately, Bieber remains mum on her in the interview. He did, however, talk about another brunette beauty — Kim Kardashian, who he became friends with after posing alongside her for an Elle photo shoot in 2010. "People say she doesn't do anything; she actually does do stuff," Bieber says in defense of the much-maligned reality star. "She works hard." Bieber's had his own share of haters, and he seems to know it. "I mean, I keep my guard up a lot, because you know, you can't trust anyone in this business," he notes. "That's what's sad. You can't trust anybody. I learned the hard way." Michael Fassbender's Sexy GQ Cover Shoot Peggy Sirota/GQWhile statements like that make Bieber sound like a true showbiz veteran, his career has been relatively short. His new album Believe, which comes out June 19, is his third full-length collection of songs, after 2010's My World 2.0 and November's holiday album Under the Mistletoe. However, no one is more approving of the Bieber archives than Bieber himself. "I've never made a bad song," the teen declares. He's so serious about his work, that a producer even says Bieber doesn't get his feelings hurt while recording tracks, he "hurts feelings"!