My daughter came out as gay about 6 months ago. She was 13.
I have no problem with it, and was sad actually that she had felt she had to get up the nerve to tell me.
BUT for the 6 months or so before, I could see she was really struggling with something. I could tell from various comments that how she looked, her identity and gender was playing into it, and that it was a really hard time for her. She wouldn't talk about it, and if I did comment, I always seemed to say the wrong thing.
When she told us, it was like a damn bursting. We had a couple of months of hundreds of gay pride comments, rainbows everywhere etc, and it became a bit of a standing joke between us - so when watching a programme she would try and spot gay characters before you knew they were gay. She would say - yeh how about him? (or her) and I would say - yes or no, or definitely - look at the rainbow tattoo, or whatever.
In other words, we normalised it, accepted it, let her know that we loved her as she was, and then it all calmed down. Now she is much more likely to talk about school/friends/music than being gay. She is only 13!
I guess what I am saying is, if your dd is struggling to work out who she is and what she is and how that fits into the world, she may just need a safe space where she knows you love her and accept her whatever is going on. If you saw it from family videos, I would find a time to sit down and say - I saw it on the videos and I want you to know it is OK, I love you, it is fine for you to be who you are. Do you want to talk about it?
Even if you ARE struggling, you need, for her sake to keep that to yourself at the moment and support her. You can't change her, and disapproval will only drive her away. She is who she is, let her know your feelings haven't changed.
We come from a background where some people will not accept it.
I have talked to her about this. She has decided to not come out in one or two contexts at the moment. But I have also told her that we will back her to the hilt in any context, and that if anyone does give her any trouble, send them to us!