How can i tell if she likes me more than a bestfriend?

Does she like me as a bestfriend or more?
Theres this one beautiful girl that i like but i dont know how much she likes me.
She jokes around calling me bestfriend and everyday says hey bestfriend or hey bff really loud out in public lol.
One day she chose me for her partner if that means anything.
However, when she sees other guys she doesn't say that so it seems im the only guy that she says it to.
Also, we talk on facebook every now and then until i get off and hit the sack.
Is it possible that shes into me?
I've only known her for 1 year.

i like her and i would like it to go farther in the relationship but i dont know if its a mutual feeling.