All perfect praise be to Allah, The Lord of the Worlds. I testify that there is none worthy of worship except Allah, and that Muhammad is His slave and Messenger.
Persisting in not praying a given obligatory prayer is Kufr (disbelief) if the person is aware of this ruling. The fear of non-Muslims is not a reason for leaving an obligatory prayer.
Know that the obligatory prayer is mandatory in all circumstances. If Muslims were to be allowed to leave an obligatory prayer, it would have been during the battle with the enemies of Islam.
In fact, Muslims have to pray even during the battle. So, merely fearing to be overwhelmed by questions or to be laughed at can not be considered reasons for abandoning an obligatory prayer.
In fact, you should – while praying – have in mind that you are standing in front of Allah, The Almighty, and then not give any importance to what the people would think of you as long as your aim is to please Allah. But if it is impossible for you to perform this prayer with these people present, then you should try to find a quiet corner in the school or outside it where you can perform your prayer.
If you cannot perform the prayer at its prescribed time, then you have to move to another school where you could perform all your Islamic duties.
For more benefit on the ruling on abandoning the prayer or delaying it, please refer to Fataawa 384457, 377344, 88016, 84178, 83565, 87587, 90926, 88690 and 84403.
Allah knows best.