Why do i care so much?

I know this woman that is like my second mother but i think is at a mid life crisis. she 53 and still likes to go out and drink on the weekends with her girlfriends and i mean they really drink not just have a few. Im 23 and rarely drink, im not saying she be more like me but i just dont know why i have to care so much if her husband doesn't care that she goes out. Why does it bother me? I never see her out at a bar because i want go when they ask because i dont think i want to see someone i care about drunk. Shes also a good looking 53 three old woman and says she has younger guys coming up to her and flirting but does not cheat in anyway on ehr husband. But still Why does this bother me? Why cant i just not care about what she does and just live my life the way i wnat it and let her live her's?