Most Helpful Guys
Yes, you can stop sharing your location in the Find My Friends app without it sending a notification. You may not be able to turn it off for her specifically without notifying her but you can turn it off altogether which will hide it from everyone and it shouldn't notify them in this case. It can be temporary or permanent, it's up to you.
To do this:
1. Tap Me.
2. Turn off share location, and then tap okay.
When you turn off your location like this, "not available" will appear below your name on the devices of everyone who follows you. It will be like when your phone is turned off or simply offline. This should solve your problem with your friend without directly notifying her and causing drama.
There are a lot of apps which runs in background, and you would never know. Better you install it in her phone and then you can take control of her phone and you would be able to delete those messages through your phone, cheer up girl ;-)
Most Helpful Girl
Tell your friend to get a life and stop stalking you. Or just block them from the app.