Hello preeto ma'am

Im in some serious dilemma ... Im 21 .. I recently asked a girl out !!! She and I are friends since long...I had a lot of expectations and thought that she would definitely say yes !!
But to my bad luck she said no..And I was shattered..I have loved this girl all my life and never thought of anyone else..
I dont know the way ahead !! I do agree that i didnt ask her out in a very appropriate manner and it was very haphazard...But that cant be a sole reason for rejection
She says she never thought of me more than a friend...and wants things to be same
Knowing her stubborn nature she rejected me and said not to even try again !!!
Im all lost !! How do I go about ????
I dont feel like letting her go as Ive been hanging with it since long and truely love her !!
We r still good friends ....

PLZ HELP AT THE EARLIEST