The first 90 days in a new senior role are an imposter-syndrome accelerator: new domain, new colleagues, new context, and a strong drive to prove the hiring decision was correct. Five things that help:
1. Permission slip for incompetence in week 1-2. You will not understand the codebase / the customers / the org politics. That's not a personal failing; it's the structural reality of being new. The hiring committee KNEW you wouldn't know. They hired you for what you'll do in months 3-12, not what you do in week 1.
2. Write down what you don't understand. Keep a running doc: "Questions I don't yet have answers to." This converts vague anxiety ("I don't get this place") into concrete tractable items ("I need to understand why the team picked Postgres over DynamoDB for X service"). Anxiety hates specificity.
3. Ask the obvious question in every meeting for the first month. "What does TLA mean?" "Why did we decide to do X this way?" "Who owns Y?" People remember these as evidence of curiosity and intellectual honesty, not stupidity. The window to ask "dumb" questions without consequence closes after month 1-2. Use it.
4. Avoid premature opinions. The new person who has strong opinions about the org's mistakes in week 3 is universally annoying. Withhold judgment for 60 days minimum. Take notes. Form theories. Don't share them yet.
5. Find one quick win to ship in month 1. Doesn't have to be huge. A documentation gap closed, a tooling annoyance fixed, a meeting you streamlined. The point is to feel like you've contributed something concrete. Confidence comes from shipping, not from thinking.