I agree that it is way to early to do proforma. You can do it at anytime and you may want to overwrite those that you had done earlier. Personally I aim for doing it either early January, or if your client base is small, doing each as needed since updates change what the proforma does and how it does it.

https://proconnect.intuit.com/support/en-us/help-article/manage-client/using-proforma-wizard-transfe...