I think I was 35 when I first said to myself: "When you don't understand something, it's either because it's difficult, or because you don't have all information you need yet."

Being able to think this (and really feel it) was a big step for me. I think objectively I was always quite smart and also highly educated but I still felt like an imposter. It's nice when you finally feel that trust in yourself. And indeed I probably sometimes look stupid, but I think I often come back quickly in smart ways afterwards anyway, so I don't care so much about it.