Are you surrounded by people who inspire and achieve in any of your circles of people today, or have you been in the past? In those instances, did you inspire and achieve? If not, were you surrounded by those people for long?
When you are trying to achieve something hard, do you need any more challenges to make it harder? Do you need to fight off doubt to achieve your goal if you didn’t have to? Would everything not be easier to achieve if you only fully believed you could do it, whether from the start or from somewhere along the way? Those are the reasons why you should believe, before you achieve.