why did this hurt my feelings so badly?

so let me start from the beginning, this guy moved in my neighborhood about 3 years (2010 or so) agoand every since then ive had a crush on him, hes goregous, the most beautiful human being i ever did lay eyes on (im being a tad dramatic but he really is goregous) anyway ive had a crush on him for a very long time and about two years ago my friend down the street told me his name and i used to yell hi to him down the street, i did this maybe six or seven times. anyway on my birthday of 2011 i belive my cousin told him it was my birthday and he said happy birthday to me (i almost died by the way, im really shy around guys) so anywhos i hadent really talked to him ever again after that and then in 2012 i tried to start a conversation with him and he didnt reply. so last month some time i messaged him again in the hopes maybe he would reply and he didnt. so today i saw him and it just interested me to know why he hated me so much. so i went on facebook and asked him if i said something wrong to him or something and he said no why so i told him that he ignores me and kind of brushes me off when i try and be friendly, and his reply was im wayy too young so i told him im not that much younger than him and i just want to be friends and he read the message and never replied. hes only 3 years older than me which to me isnt that big of a difference but i dont know. but anyway after that i ended up crying because it hurt my feelings and upset me and i dont know why because i know he didnt mean it that way. (btw im 16 hes 19)

can someone explain to me what i should do. and why it hurt my feelings so badly. has anyone else had a problem like this. any suggestions for me. thanks. also please no rude comments