why did she block me on facebook?

[CooL GuY!!]

i saw this girl in an ad and she is average looking, but i dont know why i fell for her.... she is a model for advertisements in internet.. i guess she is around 16-18... and i didn't even know her name and i found her later in facebook after a large research....
i don't love her but i just wanna be her friend... so i messaged in facebook saying hello, i'm your fan and you are extremely pretty blah blah... i didnt misbehave nor did over action to flirt.. its just a casual message .. she didnt reply and blocked me.. it saddened me
i searched for her name for nearly many months... but i'm just hurt she blocked me.. she is a popular girl and probably she has many fans and followers.. but why did she block me?

i'm not that bad looking nor a stalker... i'm 19 years old and when compared to her, i look better...

i have another facebook account and wanna message her again asking why she has blocked me.. what if she blocks again? what should i do not to get blocked again? how should i message her?
shall i ask why did she block me? please advice me.. i just wanna talk to her ..