My mom can’t keep secret

My twin sister and I are handicap so, it’s easier to ask mom to get stuff for us. I asked her to please get us fast food and she said ask your step- dad, but we told her no because that makes us uncomfortable. She ignored us and asked him anyway. Than called us back and told my sister to go with him because she asked him for us and he said it was ok. Ignoring our protests yet again. Is she right in saying we shouldn’t be mad even though she completely ignored our feelings?