A friend who is mean and now she is nice?

i have a friend who was mean to me and her name is demickia and she bulled me and she is 10 year old she is small and she is so mean and one day she gave me a note in cl that said you are ugly and i hate you and i am not your friend and you are a bic and i side ok so and she worte back and said shut up and wirte and i said you no and she is a liyer what should i do she is mean to me and now she is nice so she calles me she said that i am rude she is rude i hate her