Gosh, what should I do about this feeling?

Hi. Sup? I'm Chen (pronounced Wen), new on answers. I do not know how to express these feeling for girl I like. Her name is Lauren, and she's my best friend. She comes over almost everyday but more on weekends. We always hang out. My bro never shuts-up either. He says, "Sup? YEA! Go Chen and his girl!" or he says, "Chen, how is your wife doing?" I smack him in the face, but jeez, this ain't helpin. When she first came over with my cuz I fell in love. She's my gal.. I really want her to know how much I care, dunno how. I like her personality, eyes, smile, warmth, comfort, everything about her. I cud, though, screw this up. We hang out all the time, and I cud ruin that. I remember the first day she came over, after we drove her home, she hugged me when I led her to the door, she said, "Love ya." but of course as a friend, ya know? My family has nagged on me ever since about me & "my girl", I argue wit dem 2. Truth is, she is "my gal". I want to tell her, but am unsure. Wut shud Chen do??