17 year old runs a study channel with two friends and hasn't mentioned it to us

My daughter is in class 12. On Sunday I switched on the TV and the video app opened on a channel she runs with two friends, still logged in under her account. Recorded study sessions with the camera on their desks, some talk about college applications, a few hundred followers. We had no idea it existed. I watched about two minutes and turned it off. Part of me thinks there is nothing to discuss. It is schoolwork, she will be 18 next year, and three girls revising together on camera is not exactly a worry. The other part would like to know whether her face, her school uniform or anything about our area shows up, because anyone can see it. If I raise it, she will know I saw it, and she may feel we are checking up on her a few months before she is legally an adult. If I say nothing, I am pretending not to know something I do know. I would rather have one calm conversation about what she shares than ask for any kind of access. I just haven't worked out how to start it without it sounding like I was looking.