Is the fast of a Muslim who did not partake in the pre-dawn meal (suhoor) valid, and why? And did the revelation of the Holy Qur'an begin in the month of Ramadan?

The fast of one who did not have suhoor (pre-dawn meal) is valid, but it is disliked for him to abandon suhoor because it goes against the guidance of the Prophet, peace and blessings be upon him, who said: "Eat suhoor, for in suhoor there is blessing," and his saying: "The distinction between our fasting and the fasting of the People of the Book is the eating of suhoor." The Holy Quran was revealed in the month of Ramadan, as Allah Almighty says: (The month of Ramadan in which was revealed the Quran, a guidance for mankind and clear proofs for the guidance and the criterion (between right and wrong)).