Nobody remembers who hesitated at the open mic. They remember who got up.

The people in the room are not keeping a record of who thought about it. What gets remembered is the person who stood up, and usually not even what they did up there, just that they did. The hesitating is a private event, which protects you from nothing and costs you the thing you wanted.

Put your name down for something where getting up is the whole achievement: an open mic, a reading, a question at an assembly. Decide before you arrive rather than in the moment, since the moment will always argue against it. Being bad at it in public is a perfectly good outcome.