Hi Hannah92.what doctor are you trying to say? Is it a doctor of medicine? Or a doctor of philosophies? We have different types of doctors. If you were trying to ask of how hard is it to become of a doctor of medicine,well it is really hard because you have to go through many examination and more to that you can't pursue doctoral not unless you are a graduate of BS medicine or BS nursing..But if you were planning to be a doctor one day then you just have to have faith in yourself, study so hard and strive hard and for sure you will reach your goals..