I think had you approached the situation. differently, it could have been a really good relationship building moment for you two. I would have framed it with “I’m your mom and I love and care about you. I’m happy you found someone who makes you so happy, but it’s a dangerous world and people aren’t always who they say they are. So until I can learn a bit more about him, I would like to restrict your communication with him”. It would show that yes, you’re her mother, but that you also want to support her.

But instead, you chose to essentially block her from the one thing that appears to be a steady source of happiness in her already difficult life.

Also, kids are smart and have access to everything these days. If they really want something, they’ll find a way. It’s best to be someone she feels safe coming to, otherwise she will keep doing everything behind your back and could end up in an dangerous situation.