Is it legal for my mom to not let me have any dinner other than the dinner my sister makes?

r/

Location: New Zealand. So my sister is very unhygienic and doesn’t wash her hands after going toilet and only showers like once a week. She sometimes makes dinner and i dont want to eat it. It’s unfair since no one cares everytime my sister just microwaves something after I make dinner. Now my mom isn’t letting me have ANY food until I eat her dinner. She said I can either eat her food or go to bed. I try making a sandwich and she takes the bread off of me. Is it legal for my mom to not let me have anything else at all in the house until I eat my sisters disgusting food?