Why cant I get a girl?

I consider myself to be a nice guy, but I'm not one of the jocks...even though the jocks are my friends...I usually hang out with the guys I personally consider my friends and don't hang out with the jocks just to look "cool" and hang out with them once in a while too...I don't smoke...but an occasional beer is good for me...I'm 16...I'm tall and I'm not fat...I have the got the reputation of "the good guy" or "good friend" and I don't get into trouble...if I sense a fight is about to start with me and another guy I just say "I was kidding man.Relax"...but I don't get good grades...I make a fool out of myself when I'm around the girl I like..like I make dumb-*** jokes and try to be the guy I personally am not...when I ask a girl out she just says "I'm sorry,but your just a really good friend" even when I barely know the chick..maybe its cause I'm an ugly duckling but I've seen guys like ringo starr marrying a bond girl...after that I believe anything is possible...but after the girl rejects they all give me a reuring smile whenever I walkby or anything and tell me personally that " ur a really nice guy and some girl would be lucky to have u" and other crap from the movies...I'm just tired of this! are looks really all that matter or do u have to be in the football/basketball team to date...this is just f*cked up..