she is a leader of the church. She has the same confidence rules as a therapist does. She can't break that without running the risk of losing her ability to serve in a church.
I could be wrong, but I don't think most youth group leaders are bound by confidence rules like therapists - or at least not the the extent that, say, a priest would be. But it probably depends on your particular church, and either way I can't imagine it would go over well with the higher leaders of the church, to infringe upon a member's rights and privacy like that.
If your leader would go against your will by attempting to report, thinking it was her responsibility to "protect you" by taking it upon herself, then perhaps she is not the best support for you at the moment. That is highly insensitive and inappropriate at best, and feeling like you are being forced into something can be really difficult for rape survivors to deal with. You have the absolute freedom to report or not. If you don't think she would respect your decision, then however great she might be in other areas, perhaps she is not the right person for you to approach right now.
This is a really tough situation. I'm so sorry you're dealing with it.