Smoking with daughter and friends?

I overheard these group of high school seniors talking about their friend's mom. Since they're seniors I assume they are 17 or 18. They were talking about the time they went to that friend's house recently and the mom asked if they wanted to smoke weed together. Another girl said they always smoke together and their friend's mom greets them with "Whats up my bitches" Overhearing all of this really annoyed me because what is a grown woman doing smoking with like, 18 year olds? And referring to them as my bitches? They're not your friends and they're not her equals. The whole thing just seemed too weird for me. And smoking with your KID? Wtf. Couldn't be me lol