Life, as we know it is a risk, waking up in the morning to step out there into the open world, is a risk. Not everyone who goes out comes back home so you should understand my point. When you eat there is some amount of risk involved because that food could literally choke the life out of you should things go south or the wrong pipe.
I've heard stories of people who even died in their sleep, which makes even sleeping a risk that we take everyday, we go to sleep with all hopes that we would wake up the next morning, but have you ever asked yourself what happens if i don't see the break of dawn again. Life is too short as they say for us to spend it on fears and unhealthy mental thoughts.
You only live once irrespective of your religious believes, yes some believe in the after life and eternal life after death, others in reincarnation, etc, but the truth is basically that you only live once, once you are gone you are gone. So don't be afraid to take certain risks in life especially when those things go in line with your dreams, goals and aspirations for your future.
You want to be a medical doctor take that risk and apply to that university, don't say i am not worth it or i'm afraid i won't pass the entrance exams, so what if you pass? Have you though about that too? You have seen that beautiful young lady, you really want to go out with her but you so afraid as if asking her out will cause you damnation.
Please give it a try, there is no reward without risk, who knows you may just be that lucky guy and the prince charming she has been waiting for. Take those risks, they are health risks and they are meant to go positive more than negative when at first it doesn't work out try again, persistence brings victory.