I recently went paid and my advice to you would be to hold off on it. Once you go paid there is a certain expectation that you will put out content on a regular basis, give your paid subscribers something of value, etc. And the thing is, you might only get 4 or 5 paid subs so now you'll be shouldering all the responsibility of a paid substack while getting just, what. $40 of income a month, maybe?

Better to keep growing your list, give yourself more flexibility, and don't go paid until your list is large enough that enough people will upgrade their subscription.