Huge crush ...what should i du?

i`m a 16 r old gurl...2 yrs ago this guy out of the blue came ova 2 me en introduced himself we talked and talked but then i had to go so i left b/c i was wit ma cuzn then i saw him a few days l8ter he was wit his friends and i was jogging....he stopped when he saw me but i just smilled and kept on runnung....ever since then he neva stopped invading ma tots..i think about him all the time and i have him on face book but he doesnt knw its me....i crush on guys but neva like this...should i tell him or ask him outi ,mean it was two years ago...