Teen sensation Justin Bieber says he was terrified when he first kissed his girlfriend Selena Gomez. The 18-year-old singer has been dating Gomez, 19, since 2010. Bieber said he was very nervous but was left smitten by the kiss. "It was scary and spontaneous and it was just awesome. It was the best kiss of my life," dailystar.co.uk quoted Bieber as saying.