I think I am about the same age as you and @cecicastor and I also remember that feeling. Not because my parents were so demanding, they were not. In my case, it was because I was a woman. That made me think: "I am not good enough'.
In education, it was a man's world and I became one of the first women as a principal (You can imagine how long it took before I dared to apply).
I felt I had to be twice as good as a male principal. It took a while before I could believe that I was good at what I did. That helped me enormously, but even then I sometimes experienced the feeling that everybody else was better than I was.