Why do i keep having dreams about her?

well, i know this girl from 9th grade. the first time i saw her she smiled at me and me being shy didnt smile back. but aftr a few weeks i asked her out to see a movie(the only time i evr spoke to her in person, we talked on myspace a little bit) she said yes but had to cancel because her family was coming into town. i havent talked to her since, but we've crossed paths ovr the yrs in school. our cl just graduated and she is now in college. i had kinda put her out of my mind for a few years during school, but now all of a sudden im having dreams about her. nothin weird...we're just talking or shes just randomly there in a dream and ill say hi or something. i want to talk to her again(only way i can think of is facebook cause she lives on campus where evr shes going to school. im hesitant because idk if she remembers me, and if she does i feel as though she remembers me as the rly shy kid who nvr talked to her evn though she knew i had a little crush on her. so theres a few questions, the first of course being; why have i suddenly started dreaming about her. second question...well its not rly a question...i need some advice...im not tht experienced with talking to the opposite ...thanks