What kind of schooling do you need to become a cop?

i am a 19 year old young man and i spent most of my teenage life running around in the streets kicking it with gangsters and Smokin up... but now i see i made a huge mistake growing up. i dropped out of high school, but i'm looking to get back in school to finish the 14 credits i still have to do. i was just wondering what kind of schooling do you need to become a cop? and is there a faster way for me to finish school with out going back to high school this september?