The job description Bezos wrote for his very first employee said, “You must have experience designing and building large and complex (yet maintainable) systems, and you should be able to do so in about one-third the time that most competent people think possible.
If you're the CEO of a fast-growing startup, the mistake you'll make in the next year that you'll regret most will probably be a hiring mistake. Possibly hiring someone established, which you'll feel you should do now you're getting big, and which VCs will strongly encourage.