I think what I'd do is probably just take some basic flat lessons just to turn your postition into a more "English" position and just get used to a different style of riding. Then I would start taking jumping lessons once you're ready and then X-country etc. It may take 1 year or a few depending on how fast you pick it up and your dedication! Good luck!!
Thanks! But I'm wanting to start and English eventing career. But I have looked into cow horse work as well including reining and cutting. I'm wanting to start fresh with new disciplines and am no longer wanting to proceed in barrel racing. But I really appreciate your response!