i agree with notransfer on this one, the 15 y/o sounds like your best bet, how long you been smoking with her? a lot of people are quiet and stuff if they haven't been smoking that long, but after a while they open up in my experiences, getting her talking is a good idea, get on the right subject and relaxed and you'll prob have the craziest long ass conversations ever. all time and patience, but at the end of the day the choice is yours