I think my best friends crush like me?:/?

Maybe you should talk to your friend about it first see how she feels, if you have been hanging out together allot im sure she has already picked up on it. Friends will last longer then a bf and you sound really young so trust that there will be many in and out of your life. If you value your friendship talk to her about it first just ask her why she likes him and how she would feel if one of her friends started dating him. Or just wait it out soon enough she will lose interest and be after some other guy and you can then move on with him without the guilt. Good luck