Legal Question in Civil Litigation in California

If you do not want anyone to know, there is not much you can do. You can't stop her from talking except by paying her. If you want to do something about it, then you will have to put your dignity aside. If you are willing to do that and she is charging illegally high interest, she is guilty of loan sharking. You can file a police report, you can sue her to cancel the debt, or you can just stop paying her and if she sues you then plead the illegal interest as a defense.

It is confusing from your post whether you are loaning her money at a high rate of interest, or she is loaning you at a high rate of interest. If she loaned you money at a high rate of interest, she may or not be guilty of felony loansharking, but getting the police to arrest to charge her is an uphill battle. If you want to sue her civilly, you can sue her for Usury, assuming that she does not meet an exception. This involves penalties, such as voiding all interest payments, treble damages, and money had and received. If the interest payments are voided, it means she cannot charge any rate of interest, including a legal rate of interest. At that point, you will probably be declared to owe her nothing, as all of your prior interest payments are applied to principal.