When someone gets shot intentionally and dies, does he die because of the bullets or does he die because it was time for him to die?In other words, can one die before the time prescribed by Allah? Or is the time preset?If one commits suicide, does he die early?

Praise be to Allah, the Lord of the Worlds; and blessings and peace be upon our Prophet Muhammad and upon all his Family and Companions.

The most correct opinion in this concern is the opinion of the Aha-ul-Sunnah. They believe that the time when a person killed by committing suicide or by being murdered, or by any other means, it is the appointed time of his death, and that time is predetermined from Allah. No one can delay it nor advance it. This opinion is supported by Sharia and the intellect agrees with it. Allah Says (interpretation of meaning): {And every nation has its appointed term; when their term is reached, neither can they delay it nor can they advance it an hour (or a moment). }[7: 34].
The same is in Surah Yunus: {Say (O Muhammad SAW): "I have no power over any harm or profit to myself except what Allâh may will. For every Ummah (a community or a nation), there is a term appointed; when their term comes, neither can they delay it nor can they advance it an hour (or a moment)." [10: 49]
It is narrated in Sahih Muslim that the Prophet said: "Allah ordained the fates of the creation fifty thousand years before He created the heavens and the earth".
It is narrated on the authority of Abdullah Ibn Massood that the Allah's apostle, the true and truly inspired said, "(as regards your creation), every one of you is collected in the womb of his mother for the first forty days, and then he becomes a clot for an other forty days, and then a piece of flesh for an other forty days. Then Allah sends an angel to write four words: He writes his deeds, time of his death, means of his livelihood, and whether he will be wretched or blessed (in religion).
The above mentioned evidences and many others that we did not mention establish the truth that the predestination and its reasons are determined by Allah before creating creation. "To Him belongs whatever is in the heavens and whatever is on the earth… He knows what happens to them (His creatures) in this world, and what will happen to them in the Hereafter. (2:255)". Nothing occurs, except what He has determined and in the way He has determined and at the time he has specified for it. None can change it neither delay or advance.

Allah knows best.