Justin Bieber has been receiving rave reviews for his new album Believe due to its more mature sound, but does Bieber, who skyrocketed to fame at just 15 years old, feel grown-up?

"I mean I'm 18, I'm growing as an artist and my fans are growing with me so, I'm just making music that reflects that," he says. "I feel as grown-up as I can. I mean I moved out, I'm traveling, I have more responsibility ..."

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And what's the most grown-up responsibility the Biebs has had to deal with so far?

"Taking care of my house," he reveals. "Like having to call people and making sure the yard is good, everything is good."

As for all the talk about his first smash single from Believe, Boyfriend, marking a sexier sound for the superstar, Bieber believes he is more than ready for the evolution of his image.

"I think that the song is definitely a sexy song. I mean to have the whisper rap in the verse coming into the hook, I think it's definitely a more (grown-up) song," he says. " I think that I'm definitely ready for it, being 18. I'm not being overly seductive or anything. I think I'm where I'm supposed to be."

He does get testy however when it comes to his girlfriend, Selena Gomez, when he's asked if it's really necessary that he picks her up from the airport (which he's been photographed doing numerous times) given the hassle his fame creates instead of just hiring a driver.

"I mean it's just like, would you send someone else to go pick up your girlfriend from the airport? Do you think she would be happy with that?," he asks. "'Oh yeah, I'm just gonna send a driver, he's gonna come get you ... I haven't seen you in about three weeks, it's all good, I'm gonna send a driver.' No. I mean, I think that would be kind of rude.