You're 13 ok cool. Umm at 13 you really dont expect any romance. I assume that you want love in a relationship or do you just want a friend to hang with? Prehaps the girl that seems nicer to you just understands you better. Maybe you click easier with her. Ask yourself do you feel more meaningfull around her? Does she relate to you better. Who is easier to talk to and who do you feel most comfrontable around? Make friends with both of them. Its completely mature and acceptable to make friends with opposite sex persons. Just be friends to both of them. Maybe one day who ever is right for you or fits with you the best will be more than just a friend to you. If they are true friends then they dont have to be your lover....

Just have fun and be friendly to both. If one feels more right for you or easier to "click " with then I suggest that you try to get closer to that one 1st. Dont go over board.