"I was going through my 15-year-old daughter’s phone (I believe parents have the right to know what their kids are doing/seeing online)"

Hey, my mother believed this too! She also would go through my phone and my emails and, memorably, told me she would have the right to read my diary because it's important to her to know what I was doing so she could keep me safe.

Also, several years on, I still will not tell her anything important about myself.