After looking through your examples, I would say there’s nothing that should keep you from starting to do character commissions. You already have a bold style and easily recognizable color scheme.
What I would recommend is sitting down and coming up with a basic plan and guidelines for yourself. What do you want to draw? What won’t you draw? Will you require a downpayment? How much do you want to make an hour (which then requires figuring out how long it takes you, materials, etc.)? Where will you advertise? Etc. I’d recommend Paypal. Thus far, in the world of online shenanigans, it’s given me little to no trouble.
The overall look and feel of your characters is striking. I would recommend though, if you’re serious about it, doing some intensive sketching work (digital or in a notebook) of anatomy. From personal experience, drawing what you see is the first step in art. The second would be the nitty gritty, if you’re looking to do characters, of knowing anatomy. Reference photos are important but in composing new characters, eventually you’ll have to invent something. To make it convincing, comes from hours of having sketched the real deal. You build an extensive inner knowledge. NOW, none of that was to say your anatomy is terribly off. At all. As someone who’s actually on this journey, this is what I’m running in to in needing to work on. In my opinion, that is what eventually will set someone apart in the digital world; that basic knowledge of anatomy. Robert Marzullo has a lot of really great Youtube tutorials that help you build basic figures and work on anatomy. The Andrew Loomis method is also extremely helpful.
You do not have a soul. You have a body.
You are a soul. - C.S. Lewis