What’s considered child ****? And would this be considered child ****?

This boy claims to have videos of me (he’s 16 turning 17) but I only sent him a video of me doing a live twerking in the classroom (I was wearing a shirt, jeans, and sneakers) I’m 17 gonna be 18 and he’s claiming that he’s gonna use it against me if I mention his name to the cops (because he was threatening a boy) but I wasn’t gonna tell them that I was gonna tell them that the boy also had physical altercations with the boy I’m reporting. He was quick to switch on me and threaten to not mention his name and that he’ll show the cops my live video in the class and that he knows the laws (but doesn’t because if he has child **** in his phone then he’s charged with it too) and claims that I’m done and that he didn’t do anything (even though I have several messages of him threatening the boy)