The reason I think it is fair to call it an AST interpreter is that there is roughly one function call for each AST node. This isn't necessarily a bad thing tho

The reason I think it is fair to call it an AST interpreter is that there is roughly one function call for each AST node. This isn't necessarily a bad thing though -- AST interpreters are super simple and maintainable (as you have demonstrated) so if you got good performance out of one then it is great!