As I had my first child, I promised myself never to be a pushy parent. I was going to be a very patient and understanding mother.
Five years later my little boy was about to test for his yellow belt in karate. As a five-year-old child, he wasn’t taking itseriously, because it was Mom trying to help him. I found myself yelling and telling him he would never get the belt acting like that. I was trying to teach him his back-flip. He continued to play and I continued to yell. Finally I had made him feel like he couldn’t accomplish anything, just as I promised myself I wouldn’t do.
Still mad and stubborn I couldn’t 1 . I had to teach him his flip.
A. give in B. give up
I think both answers are acceptable. But the answer given is "give in" .
1. What does a native think of it?

2. Also what does "just as I promised myself I wouldn’t do" mean in the second paragraph?