What are the reasons she denied my friend request?

[Telle]

It's no biggie, but I'm just curious. I lived in a small town so everyone basically knows of everyone. So on Facebook we can see that visually. Anyways, there's this girl I had art class with senior year. We both know of each other, cause we've talked a few times before but other than that she would just look at me across the room while we talked to other people.
I thought she liked me for some reason but I ended up on her Facebook page one day from looking at comments and I saw 'friend request sent' so I figured she didn't see the add a whole ago, or she denied it. So I just sent her another request incase she forgot and she denied it. I knew she was online cause she liked one of my friends statuses when she didn't add me again.
What are the possible reasons for that? I was kinda popular highschool girl by the way, so I'm sure she remembers me. But who knows lol. Any thing similar happen to you? Thanks

[tumbleweed_biff]

You will need to ask her. None of us are psychics.

[?]

she doesnt like u or want u seeing her profile. she sounds like a bitch for not adding u but being nice to ur face