Ask HN: SaaS chatbot for free vs. charging users – what should I do?

Hi, I am founder of chatbot startup - it's fast growing, we are getting a ton of users signups, and almost 0 churn rate!

As a founder, I am confused between 2 roads: a- make it fremium/free for the sake of increasing the number of users, and then gradually increase it year by year through the next 5 yrs.

b- Make free very limited, and start charging users from day one, just like other chatbots. But this means I will get a small number of users.

What should I do? I am really having hard time making that decision!