The middle hour


I was reading the Signs of Last Hour in the below Islamic website. I came across a Hadith given in the website which is as follows :
[Some Ahadith report that the Prophet was asked about the Hour. He looked towards a young boy and said, "If he lives, he will not grow very old before he sees your Last Hour coming to you." By this he meant their death and entering the Hereafter, because everyone who dies enters the Hereafter; some people say that when a person has died, his judgment has begun. This Hadith with this meaning is "correct" (Sahih)]
Does that Hadith means that the Last Hour will begin before the young boy turns old. Please advise if the above interpretation of Hadith as mentioned in the website is right or not. I am quite confused so kindly elaborate the true meaning of this Hadith.