AITA for declaring “no gifts” after relatives had already bought birthday presents?

Two weeks before my child’s birthday, I changed the party invitation to “no gifts, please” after our apartment became overwhelmed with toys. Several relatives had already purchased presents.

I asked them to return or donate the items. My mother brought hers anyway, so I kept it in the car and did not let my child open it at the party.

She says I changed the social agreement late and embarrassed her in front of other guests. I say one exception would turn the boundary into a suggestion.

The gift stayed unopened, but my child spent the evening asking why Grandma’s package was not allowed. I reduced clutter by making the rule the most memorable part of the celebration.