Me and my girl: Teen star Justin Bieber enjoys a very grown-up romance with girlfriend Selena Gomez

By DAILY MAIL REPORTER Gissa kiss: Bieber leans into his Disney belle as they smooch in the sea He's just 17 years old, but as a world-famous pop star Justin Bieber has seen more of the world than men twice his age.And as he frolicked on the beach in Maui with his young starlet girlfriend, Disney star Selena Gomez, 18, with her arms and legs wrapped around him, he certainly seemed older than his