HOW TO TELL THIS GIRL IM NOT INTO HER!!! GIRLS ADVICE!!!?

Okay well i went to this girls house party and while im there her friend keeps telling me that (xxx) really likes me and that i should talk to her. It was new years and at the New years countdown this girl was like what do you think of me and i said i like her and we ended up kissing. But i really like her as a FRIEND. Later on i figured out the mistake i made and tried to lay back and stopped dancing and sat back and she came talking to me and i said i liked her as a friend and she was crying upstairs at her own party. Her pycho friend came up to me and was all bitchy at me saying that she will hunt me down for breaking her friends heart LOL. Anyways i talked to my guy friends and they told me that I should be light on her cuz shes really sensitive. Anyways I ended up lying saying that i came out of a bad relationship and that i wasnt ready for one and that we should take things really slowly. Everything was fine from there and when i had to leave her friends pressured me to kiss her..... So i HAD TO. She keeps texting me nonstop saying we should go to the movies. I also am going skiing with her tomm!!! Should i cancel? I was gunna tell her that i thought about it and that i am not ready for a relationship. The truth is i like this other girl which i have a date at the movies today. HOW DO I TELL THIS GIRL THAT IM NOT INTO HER???