Being ashamed of not being able to do X is not a good reason or motivation for learning it!

Another mistake is the idea which the article rightly denies, namely that you have to be smart enough to learn X.

The author makes a mistake too: she thinks she can predict the rest of her life. ("I realized I actually wanted to study physics for the rest of my life.") This last idea is related to the question adults frequently ask children, "What do you want to do when you grow up?"

The limiting factor in all these cases is how genuinely interesting you find the field and how much you want to learn it now. Which is a property of the ideas and the problems as much as of your personality.