Why does the boy i like not talk to me on Fb?

Ok the boy i like lives in Europe and i like in America i go to Europe every summer and winter I saw him there and he was fallowing me my mom said he whistled at me but i don't believe her I IM him on face-book and he never answers but one day he did and just answered hi his friends IM me and i talk to them i am 10 and the boy i like is 12 he dances as i was saying i said hello i'm 9 years old how old are you its weird like his friend IMed me by himself i didn't first he did i like him so much i changed my background on my computer to him please answer fast