Is it normal, that my friend hugs me almost everytime we meet

soo, about half a year ago, i ended up talking with this girl at school, she is on her second year and im on my third(and last year).
so now were friends on facebook, however every time she sees me at school she smiles, waves, and often hugs me.
once i help'd her with some math(over skype), which ended up with her sending links to costumes(not for kids) and other clothes she would like, shes 17 and have a boyfriend and i'm 19, is it normal? and what should i do?