11 and 8 yrar old girl making out???

I told my 8 year old daughter Kaydence that her friend Madison and her could watch a movie while I cleaned the house but I didn't hear a movie playing and so I was like "That's odd" so I listened to what they were talking about and I heard my daughter say "Hey Baby, do you want to have sex?" and her friend answer her like "Sure Baby" and I took a peek in the bedroom and saw them climbing on top of each other making out!!! and then they started showing each other there private parts ( Breast, butt, Vagina )!!! But I freaked out and ran! What should I do?!?!?