Your GF overstepped her boundaries telling you what to do in the home you're paying the mortgage for. If you were married the 50/50 equity in the household still doesn't mean her daughter who's enjoying a free ride has any expectations but to follow your rules and if your GF knows you're a musician then your practice time trumps daughters sleep time. I'd wake daughter up and tell her to vacuum. I agree with Gard and Bassy here, since you're the only one paying the mortgage, they both are guests. If at 19 the daughter hasn't evolved one inch from the slime that spawned her (quote Igor from Young Frankenstein), if you have any standards you know what you have to do.....and there's a saying "the apple doesn't fall far from the tree"
