How can I become friends again?Should I?

I usted to have a friend and she was my best friend.We lived right nextdoor and played with each other every day.We did everything together and even wore the same shirts.But everything changed when this new girl named Taylor moved in. She acted sweet and nice--I even wanted to be friends with her!Then I saw the real Taylor,and it was'nt sweet and nice--it was more like mean and evil.Anyways I won't get into the details.Basically Talor was playing with sara playing with her everyday and I wasn't able to go to her house for like a whole 2 mons. straight or atleast it felt that way! Taylor said stuff about me behind my back and would always pick on me.Taylor is 15 and i'm 12,that's a age difference.No teen should be picking on a kid.Should I really become friends with sarah after what she did to me?What really got to me was that Taylor went into muy yard about 3 times,would say mean stuff to me,say that she was gunna kick my a** and beat the Crap outta me and then after that,after I was all in tears,she just left with her friends laughfing at me,and sarah(who i have been friends with for two years) did nothing,she just sat still and quiet.