Is there a great reward for the mujahid who dies in the way of Allah, and whose age has not exceeded eighteen?

The young age of a mujahid does not harm him, nor does it diminish the reward of martyrdom. This is because it was narrated on the authority of Anas ibn Malik that Harithah was wounded on the Day of Badr while he was a young boy. The Prophet, peace and blessings be upon him, said to his mother, "Indeed, he is in the Paradise of Firdaus." Allah has magnified the reward of the martyr in the Holy Quran, for He, the Exalted, said: "And never think of those who have been killed in the cause of Allah as dead. Rather, they are alive with their Lord, receiving provision," [Aal 'Imran: 169]. And He, glorified be He, said: "And those who are killed in the cause of Allah - never will He waste their deeds. He will guide them and amend their condition, and admit them to Paradise, which He has made known to them." [Muhammad: 4-6].

The Messenger of Allah, peace and blessings be upon him, also clarified the virtue of the martyr by saying: "No servant who dies and has good with Allah would wish to return to the world, even if he were given the world and everything in it, except for the martyr, because of what he sees of the virtues of martyrdom. He would wish to return to the world and be killed again."