Or, in K's words,
Tomorrow is my first day at school but I am afraid that I will fail one more time as usual [because she hadn't read every book on the Montessori list, cover to cover]. The head of the college thinks I am great, the head of the schools for children thinks the same but I feel that I cheated on them...
You've put your goals unrealistically high, K. Now, in addition, you're acting like your mother, criticizing yourself because you didn't meet them. But why did you put them so high in the first place? There's no virtue in reading everything about anything, even for a librarian or a researcher. And the only way to learn is not from books.
Did Montessori herself learn everything from books? Of course not. First of all, it's not possible to read everything. Second, all original thinkers, people who will come up with new theories, find it tedious to read most of the published material and only select what interests them. That's as it should be. Pay attention to what attracts you and you'll find your own special abilities and interests that way.
Whenever you're frightened and self-critical like this, I'd like you to cry a little for the child you were. It sounds as if you had no one to protect you from unkindness, no stability. If you saw another child who felt as you used to, your heart would go out to her. Let the little child cry a bit, too, because you will be the kind person who has arrived to protect her.
Both of these are you, of course. But the tears will lower your stress level and make tomorrow a much easier day for you.