I would not say I had a single point where I made this decision. I had the opportunity to lead a few PMs which I initially picked. I transitioned back to IC from this role a couple of times based on my interest in the product goals. My final (or I should say current since I could transition back to IC someday) decision was when I realized I was happier seeing success of my PMs than the success of the products.
The slow transition helped me prepare both with the help of my mentors and advisors, and through "learn by doing".