dude.....my dad and i were never really close......one day we went for a late night drive and he forgot his lighter for a cig.......i said i have one and pulled out my cig pack.....he was just like yer smokin now.....i was like yea sorry.....he said whatever and shrugged.....i was in the same position as u......it feels alot better when u let them kno.....how old is yer sis....if yer not too far apart then its not a big deal but if shes over 18 and yer not then maybe u should wait......yer parents arent dumasses.......from the cigar smells to the reggae stoner movies, they kno and they not saying anything....sit down with yer dad one night and just be like, have u ever smoked weed befor and just talk about the subject with him....its kinda cool cuz it brought me alot closer to my dad.....and just mention that u haver done it a few times......w/e....worse comes to worse the ground u for a bit but my parents attitude twards life is......they'd rather know up front on what im doing then do it behind their back....u find yer kid smoking weed one night so u ground them.....it doesnt mean there gonna stop.....yer gonna do what u wanna do and they know that....its life......have respect for yer parents and just do what i said if u have the balls to....how old r u...im 16