My parents had me making one meal a week most weeks when I was...11? Maybe 10? I forget the exact age, but I wasn't that old.
They would help, of course. But It was up to me to decide what to do. My older sister was in the same boat. It lead to some... unfortunate meals. Like, I learned there is a such thing as too much dill. And my sister learned not to combine recipes when making homemade pasta. But at the ages her kids are at? Yeah, they can make basic meals. Boiling pasta and opening a can of sauce and sprucing it up a bit is well within their capabilities. Making a basic salad, or even BLT sandwiches is easy. Hell, chicken fingers, fries and frozen veggies is a meal anyone can make. Because of what my parents taught me, I'm decently competent in a kitchen, and with online recipes, I can make some pretty good meals.
That being said, mom is going about this all wrong. It's not do your part and get food. It should be "these are skills you're gonna need when you're not living with me. Learn them. Tuesday one kid is making a meal with me, Thursday the other is making a meal with me, unless there's a good reason not to, like after school stuff or just being a teenager and wanting to hang out with your friends after school. You gotta learn how to adult before you're an adult"