Well Peter, you have to be honest with yourself , and the first part is to ask why are you feeling so negative toward yourself… It could be a sign of personal depression which only you can determine and should consider if it is a real problem that you may or not may have. Then you have to remember not to compare yourself to others it isn’t worth doing and only leads to more problems.
Your grades are the real issue, Bishops do not have the time to personally get to know each and every candidate, they have a board of members, some clergy a handful are lay people, and you go through a grueling interview in which you are asked some very normal to very awkward questions, and then you end up taking a psychological exam which more than likely you will not be given the results too; on top of that your grades and educational level are examined. So yes your grades do matter, not all of them, but the more well rounded your grades are, the better not only for yourself, but for you application into a seminary College which has 4-8 more years of educational classes. Then you are also judged on your work history as well, when was the last time you worked ? How long have you held a job, is primarly what is looked at , the only time the actual job matters, is if you were a manager in charge of people, or incharge of finances, as those are skills of leadership.
If you take out the religious side of becoming a priest, the process is judged more often on these issues, and even if you make the initial cut, you could be asked leave the seminary at any time for any number of reasons, poor grades, poor behaviour, not showing up to places where you are supposed to be, or perhaps someone just doesnt feel you are really cut out to be a priest. OR maybe you decide that you want to be a married man. An then you will have to struggle with do you want to be a priest or not.
But to start off a path to the priesthood already comparing yourself to someone else and then displaying signs of a lack of self worth just indicates that you need to work on yourself more first and really explore what you want to do with your life. Everyone is worthy and called to the religious life, not everyone wants to accept it, and not everyone can measure up to the level of standards that do not really determine if someone is really meant to be a priest because even if you cut the mustard in grades and smarts , it doesn’t judge your real intentions or heart, and vise verse, you may have the right intentions and heart, but if you dont measure up in education or lifestyle then you are passed up.
It isn’t good or bad, it is just the way the process is and hardly anyone will admit this.
But everything you are facing now will just follow you later, if things are bad for you now and you dont conqure your problems or learn to deal with them, they will just get worse, and if you are happy and solid now , you will be challenged later with how to answer and lead others who are not happy or are dealing with worse.