No — asnotes, many of the best founders seem fairly introverted, especially in the early days. Later, all the great ones get good at selling — at least selling their vision. And become seeming extroverts once they do. But it’s not fatal in the early stages.
But … if you are an introvert, what will happen is the other partners at the firm won’t think as highly of you. The ones that just get to know you in 20 minutes at a Monday pitch, or in a quick meeting before. They will naturally gravitate toward the thoughtful extroverts.
So my one suggestion for the introverts — offer to help your “champion” at the VC with whatever she needs. Meet more partners before the big Monday pitch? Happy to. Want extra data? No problem. And ask your champion for help. What would the other partners want to see? What’s missing from the deck? What’s missing from the presentation? They’ll help you mold it to do better on Monday.