How to talk to your kids about social media and worldly values

My 12 year old daughter wants Instagram like all her friends. I'm trying to figure out how to protect her from the garbage out there without being that controlling dad who pushes her away. We talk about biblical values at home but everywhere else she's getting bombarded with lies about what makes you beautiful or successful. Any of you dealt with this? How do you teach them to have conviction when the whole world is against it?