To cut a long story short my daughter was invited to a sleepover. The mum who invited my daughter has a teenage daughter who is wild. She held a house party at her friends house and the friend ended up in a&e from taking drugs. The mum that I know told me that she went to the girls house and hid evidence of drug taking so that the parents wouldn't find out and stop their daughter from being friends with her teenage daughter (she told me this herself). Mainly for this reason I politely made my excuses. I told my mum my daughter wasn't going and she got really angry with and kept asking me why in front of my daughter. Obviously I couldn't explain the reason in front of my daughter (who was by now crying because my mum had reminded her how much she wanted to go on this sleepover). When I did get my mum alone and explain the reason she was very unimpressed and implied that I am over reacting. I felt really cross because my mum let me get up to all sorts as a teenager which I have no intention of repeating with my child (allowing me to go to nightclubs under age, not making me do my homework, allowing me to smoke weed in the house). I don't really blame my mum because she was a single parent and suffering from depression and I don't think she was able to be a responsible parent but it really annoys me that she won't accept I'm not following in those footsteps. She's now going round telling anyone who will listen that I've upset her because i said in front of my daughter she's just not going you don't need to ask why. I said it calmly and didn't even raise my voice. Aibu?