Because Spanish normally says tener miedo de + noun / infinitive when you say what someone is afraid of.
So de is part of the usual structure.
Because the verb here is quedarse, not just quedar.
Quedarse en blanco is a fixed expression meaning to go blank. In this sentence, the subject is yo, so the reflexive pronoun is me:
If the subject changed, the pronoun would change too:
Because Spanish attaches object/reflexive pronouns to an infinitive.
So after de, you get:
If the verb were conjugated, the pronoun would usually go before it:
So quedarme is the normal infinitive form with the pronoun attached.
Yes, it is an idiomatic expression.
Literally, en blanco means blank or in blank/white, but quedarse en blanco means:
It is especially common when talking about exams, speeches, interviews, or presentations.
Because the feeling exists now.
The sentence means that right now, before the presentation, I am afraid of what might happen. Spanish, like English, often uses the present tense for a current emotion about a future event.
So:
It is acceptable, but not absolutely necessary.
Antes de la presentación is an introductory phrase. In Spanish, a comma after an introductory phrase can be used to mark a pause:
Without the comma, the sentence is still correct:
The version with the comma feels slightly more paused or carefully written.
Yes, both are possible, but they are slightly different in focus.
The original sentence focuses on the time before the event itself, which is very natural.
Yes. In this context, presentación is the normal word for a presentation, especially a talk, oral presentation, or formal presentation in class or at work.
Depending on context, Spanish can also use more specific words, but presentación is the standard and most general choice here.
No. It is common in speaking situations, but it can also be used for memory or thinking in general.
It always suggests that your mind suddenly stops producing the information you need.