How to quickly build credibility as a new PMM on the team/in the company?

This is a great question! As a new PMM on a team or new to a company, the most important thing that helps build credibility is trust with partners in product and marketing. Building a strong foundation with your partners is critical in every PMM role. Spend time getting to know your partners and their teams - what are their goals? what is important to them? How do they like to collaborate? After you've established that foundation, the next most critical thing you can do is start to critically evaluate the current customer experience and ask questions that will help you inform your strategy and where you focus. If you do those 2 things well, you'll quickly build trust and credibility.