Sheikh M. S. Al-Munajjid, a prominent Saudi Muslim lecturer and author, in which he states the following: It is not permissible to break the fast for academic exam, rather it is haram, because it is not included in the reasons for which one is allowed to not fast in Ramadan.
Moreover, it should be noted that fasting in Ramadan is an obligation upon every accountable Muslim, and no one is excused from fasting at the time of fasting except for those who have valid excuses, who are granted the concession of being allowed to not fast, such as the sick, travelers, pregnant and breastfeeding women, the very old, and those who are forced to break their fast.
Based on the above fatwa, we can conclude that we are obliged to observe fasting during the month of Ramadan and be sure that you will have a matchless reward if you continue fasting while doing your exams. Here, we would like to mention that there are hundreds of millions of Muslims who may face a similar situation to the one you are facing and who do observe fasting in Ramadan diligently.