wow..um..just tell them that u did it and it was on accident and u didn't mean to..i mean there is a good chance they will be mad..not mad but pissed that u did it..but just explain to them...and why were u smoking in the first place?? u shouldn't be smoking in the first place. it's bad for u, no matter what age u r. but just explain to them that ur the one that burned down their house, but DON'T KEEP IT A SECRET!!!