Feeding puppy and not sure if it’s enough

I know every puppy and breed are different but how much are you feeding them? I’m following what internet research says but my mom said it isn’t enough.

I have a Australian shepherd/retriever 17 week old and we’ve been feeding him 2/3 cup of blue buffalo (three times a day) plus many treats when he goes potty outside. I’m stressing that he isn’t eating enough and I’m a bad dog mom.