Just found out my 13 year old daughter is bi

Ok. So I am a single father of a 13 year old girl. Over the weekend she had her "best friend" sleeping over and I well I walked in on them being "intimate" I told them to knock it off and that we would talk about it tomorrow when her friend had left. I didn't kick out her friend or anything but I told her to keep the door open to her room for the rest of the night. After her friend left we had a talk and she admitted to being bi. I told her that was fine and there was nothing wrong with how she was feeling. She asked me if it was ok for her girlfriend to come over and spend the night again and I told her I had to think about how best to handle this because I wouldn't let her have a boy over at her age.​So that is where I am at now. I like her girlfriend she is a nice girl who is a good influence on my daughter but I don't know whether I should continue to let her sleep over. If this were a boy I would not allow them to have sex at this age so I should i treat this differently because they are both girls? I don't know. I don't want my daughter to feel ashamed of sex or her sexuality and I don't want to do things that would instill shame in her but she is also only 13 and I just don't think it would be the responsible thing to let her have sex with her girlfriend in my house. Again if this were a boy there would be no way I would let a boy sleep over or have sex with her at this age.​The other thing is her girlfriend hasn't yet told her parents and I don't know what I should do about that either. Should I tell her parents what I caught them doing? I feel like as a parent it is my responsibility to let her parents know what she has been up to. On the other hand this is a huge thing for her to tell her parents and I am not sure I should be the one to out her to her parents. So what do you all think? Any parents of of queer kids that can help give me insight into this? How did you handle these kinds of things? I want to stress I have no issue with her being bi so if you have homophobic statements to make take them somewhere else. I will not shame my daughter for this.​edit not sure which flair is best here. via /r/Parenting https://ift.tt/2YvpmsV