Disliking a "friend"

I have friends. You most probably have friends too. And usually friends are those few people other than our family who contribute to our development of character, and success, a person who doesn't judge you...so on so forth.

However, I have a friend that I feel neutral towards. We have been friends for a couple of years, and nowadays nothing makes me want to continue being her friend other than my own guilt and thoughts. She isn't necessarily a villain or anything...it's just I don't connect with this person, and I feel that I never will.

I am sort of a family orientated girl. So to say, I focus more and love my family more than anything in the world. (By the way, I'm still very young). I've never really went out with friends or hung out with them apart from school. To put it, most of my "friends" are in all reality my "school friends". The few that I can connect with immediatly are my true friends, those who don't...feel like simple strangers that I laugh with at lunch or break.

The girl that I'm primarily focusing on at the moment says she loves me...and that I'm her best friend....oh god I don't know what to do! If I continue to smile and behave like a monotone robot about her being my best friend, where's the honesty? The relationship would be nothing more than hollow and unhealthy.

Here's the difference between us: she fangirls over things such as One Direction, Cute Boys, American Horror Story, you know, stereotypical teen girl likes. She loves social media and the works, and whenever she spots an attractive stereotypical "hot, cute" boy, she falls in love. Seriously? Since the beginning of freshman year she drooled over a decent number of boys. She constantly asks for advice, and once I contribute my opinion to her she ends up never following through with them. Wow.

She repeatedly barks about her mom, and has a sadistic rude side that hides until she speaks to her friends...one of them being me. Perhaps I might be perceiving her actions in a wrong way but I hate the feeling of being downgraded as a person, the way she speaks....urgh. To be honest, she always says she hates people and all the pretty girl etc. She even calls them words that are to be left unsaid. But what got me most, was when I hung out with a new friend, a friend that I feel comfortable with and that I have a bond with, by the time I got to lunch she seemed mad and confronted me, asking if I was her(the friend I dislike) friend. I felt hesitant and said that she was my friend, but then her hands flew up and spat out profanity making it obvious that she is "just a friend" and not my "best friend". To calm her down I said that I was her best friend.

I can't make her cry though, I don't want to upset someone and leave them with a foul memory of my existance. I just don't want to be her friend. Simple as that. Is that wrong? Is it normal? I'm sure that not wanting to be someone's friend comes with reasons, and I have my reasons...but I feel extremely and utterly horrible. Any advice? Please....?