ETA - its under "account settings" then choose notficiations on the left side, and it will then allow you to set your notifications however you want.
It's in your settings; off the top of my head I'm not sure how exactly to turn off notifications, but I know its somewhere in your privacy settings. And if you google
"turn off notifications in facebook" it will take you to a page where you can do it.
If I recall correctly, you can set your own settings so you don't get any notifications about anything, or pick and choose. Not sure why its just her, but the fact you just recently became friends with her, and the fact FB keeps changing stuff may have something to do with it.