i need some advise

ok im dating a guy right now and he is a bit younger then me and well we have been going out since nov 15. now i have know him ever since i move into bayonne. the thingy is im not sure how to tell my parents im 18 and im afarid that there going to murder me when i tell them that im dating somone whos 2 years and a few months younger then me. so this is my question. What is the best possible way i can tell my parensts im dating him? please its driving me insane and if i cant tell my parents and they find me and him together..my dad will kill me. (not really) but yeah so any advise..i know this is really dumb thing to ask but i just want to get this over with and so i would know where to go from here.