You don't just say what you want to become just like that. You first of all look at you criteria and know what you are good at and what you are not good at then you also check out what you have passion for the most.
I want to become a neurosurgeon because I always wanted to open a person before to know what is Inside
Its not going to be hard because I already have the passion to do it but yet all play and no work makes jack a mere toy