One method is getting adults you trust to stand up for you, believe you and deal with the creeps.
Some women have such a shy and timid personality that they are lambs to be slaughtered. You can’t just tell them, toughen up and learn to deal, because they can’t anymore than a real lamb can stand up to a real wolf.
Having been an overly sheltered middle-class kid, I had to find out the hard way that you need to stand up to creeps immediately. It’s a horrible, hard lesson to learn. I hope this girl makes out well!