Jeez, get all personal, wont u?!?! I'm 13 too. and of course u shouldn't do it in front of people. that's just wrong. it should be a private thing. and its not that hard. its like a short kiss on the cheek, but on the mouth and like 3 to 4 seconds longer. remember u will be holding ur breath, and u cant hold it that long.your girlfriend is very lucky to have u. Good Luck,

she definitely wants u to do it by now.