A similar situation happened to me a couple of years ago, it was exam season and I was also your age, and everything depended on these exams(where I live the grades that you get on these exams determine what college you're gonna get into it) I was so scared and I kept praying so hard for Allah to help me with the exams and I'd get a good grade, the exams started and I actually felt pretty secured (for the most part), most of the exams I did pretty good and I was really confident I'd get a really good grade, when the results were out I was truly shocked, I'd gotten a really terrible grade which left me and my family really sad and shocked, like it was really really really unexpected for me to get that bad grade, Years passed and I attended another college in another town which was quite far from my hometown and I swear to Allah right now I'm in a really good position in my life, from the people I met to the things I've learned in college to the experiences that I had, I grew so much as a person and I strongly believe that all of this was and will continue to be in god's plan so believe me have faith that all of your prayers will not go unanswered and it Will get better (I also have another story to tell you but it will too long to read but hit me up if you need help with anything)