You can file complaint or do a pre diary info to the police stating about this and you will be safe.
Before taking any crucial step, contact any good lawyer and take advices to be on safe ground.
If you are able to record her in any way she’s trying to threaten you about all of this, it can be also a solid backup proof.
See shit Happens. Life happens but we gotta act smart so it’s best to get in touch with some family lawyer or something.
And please inform her parents about all of this and also have a proof that they clearly know about all things that their daughter is doing.