Now you've told her that you've been walking on eggshells for years Nana, stop doing it.
If she starts screaming at you down the 'phone, hang up. If she does it to your face outside of your home, leave and if it's in your home tell her to leave. If it's via a text message either ignore it or tell her she's being rude and you wont engage until she stops.
You will only be a victim if you allow her to make you one. If in the future something crops up which means the original arrangements for the children have to changed, don't change them and tell her you have to cancel. If she objects, then remind her of her ridiculous reaction to this incident and that you are not putting yourself in that situation again.
Boundaries and respecting choices cuts both ways
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